diff --git a/.github/workflows/style.yml b/.github/workflows/style.yml
index 9282bb59a..f2261aebd 100644
--- a/.github/workflows/style.yml
+++ b/.github/workflows/style.yml
@@ -31,7 +31,7 @@ jobs:
       - name: Install Dependencies
         run: pip3 install --no-use-pep517 -Ur src/requirements/dev.txt
       - name: Run isort
-        run: isort -c -rc -df .
+        run: isort -c .
         working-directory: ./src
   flake:
     name: flake8
diff --git a/doc/development/contribution/style.rst b/doc/development/contribution/style.rst
index cfdf33436..995bff770 100644
--- a/doc/development/contribution/style.rst
+++ b/doc/development/contribution/style.rst
@@ -7,7 +7,7 @@ Coding style and quality
   for more information. Use four spaces for indentation.
 
 * We sort our imports by a certain schema, but you don't have to do this by hand. Again, ``setup.cfg`` contains
-  some definitions that allow the command ``isort -rc <directory>`` to automatically sort the imports in your source
+  some definitions that allow the command ``isort <directory>`` to automatically sort the imports in your source
   files.
 
 * For templates and models, please take a look at the `Django Coding Style`_. We like Django's `class-based views`_ and
diff --git a/doc/development/setup.rst b/doc/development/setup.rst
index 4a1a0715e..d00d97f8d 100644
--- a/doc/development/setup.rst
+++ b/doc/development/setup.rst
@@ -98,7 +98,7 @@ pull request nevertheless and ask us for help, we are happy to assist you.
 Execute the following commands to check for code style errors::
 
     flake8 .
-    isort -c -rc .
+    isort -c .
     python manage.py check
 
 Execute the following command to run pretix' test suite (might take a couple of minutes)::
@@ -121,7 +121,7 @@ for example, to check for any errors in any staged files when committing::
     do
       echo $file
       git show ":$file" | flake8 - --stdin-display-name="$file" || exit 1 # we only want to lint the staged changes, not any un-staged changes
-      git show ":$file" | isort -df --check-only - | grep ERROR && exit 1 || true
+      git show ":$file" | isort -c - | grep ERROR && exit 1 || true
     done
 
 
diff --git a/src/pretix/base/i18n.py b/src/pretix/base/i18n.py
index 366abd0b5..bd737e34d 100644
--- a/src/pretix/base/i18n.py
+++ b/src/pretix/base/i18n.py
@@ -4,6 +4,9 @@ from django.conf import settings
 from django.utils import translation
 from django.utils.formats import date_format, number_format
 from django.utils.translation import gettext
+
+from pretix.base.templatetags.money import money_filter
+
 from i18nfield.fields import (  # noqa
     I18nCharField, I18nTextarea, I18nTextField, I18nTextInput,
 )
@@ -12,8 +15,6 @@ from i18nfield.forms import I18nFormField  # noqa
 from i18nfield.strings import LazyI18nString  # noqa
 from i18nfield.utils import I18nJSONEncoder  # noqa
 
-from pretix.base.templatetags.money import money_filter
-
 
 class LazyDate:
     def __init__(self, value):
diff --git a/src/pretix/base/migrations/0159_mails_by_sales_channel.py b/src/pretix/base/migrations/0159_mails_by_sales_channel.py
index efab29c1b..2c18e7c1b 100644
--- a/src/pretix/base/migrations/0159_mails_by_sales_channel.py
+++ b/src/pretix/base/migrations/0159_mails_by_sales_channel.py
@@ -4,6 +4,7 @@ from django.db import migrations
 
 from pretix.base.channels import get_all_sales_channels
 
+
 def set_sales_channels(apps, schema_editor):
     # We now allow restricting some mails to certain sales channels
     # The default is changing from all channels to "web" only
diff --git a/src/pretix/base/models/auth.py b/src/pretix/base/models/auth.py
index e4d754cc9..f18cc651e 100644
--- a/src/pretix/base/models/auth.py
+++ b/src/pretix/base/models/auth.py
@@ -173,7 +173,7 @@ class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
             return self.email
 
     def send_security_notice(self, messages, email=None):
-        from pretix.base.services.mail import mail, SendMailException
+        from pretix.base.services.mail import SendMailException, mail
 
         try:
             with language(self.locale):
diff --git a/src/pretix/base/models/base.py b/src/pretix/base/models/base.py
index d679ac063..f7205e273 100644
--- a/src/pretix/base/models/base.py
+++ b/src/pretix/base/models/base.py
@@ -48,14 +48,15 @@ class LoggingMixin:
         :param data: Any JSON-serializable object
         :param user: The user performing the action (optional)
         """
-        from .log import LogEntry
-        from .event import Event
-        from .devices import Device
         from pretix.api.models import OAuthAccessToken, OAuthApplication
-        from .organizer import TeamAPIToken
+        from pretix.api.webhooks import get_all_webhook_events, notify_webhooks
+
         from ..notifications import get_all_notification_types
         from ..services.notifications import notify
-        from pretix.api.webhooks import get_all_webhook_events, notify_webhooks
+        from .devices import Device
+        from .event import Event
+        from .log import LogEntry
+        from .organizer import TeamAPIToken
 
         event = None
         if isinstance(self, Event):
diff --git a/src/pretix/base/models/checkin.py b/src/pretix/base/models/checkin.py
index 18fed1c62..1ef71be92 100644
--- a/src/pretix/base/models/checkin.py
+++ b/src/pretix/base/models/checkin.py
@@ -48,7 +48,7 @@ class CheckinList(LoggedModel):
 
     @property
     def positions(self):
-        from . import OrderPosition, Order
+        from . import Order, OrderPosition
 
         qs = OrderPosition.objects.filter(
             order__event=self.event,
diff --git a/src/pretix/base/models/event.py b/src/pretix/base/models/event.py
index 52453652b..f76adbcd7 100644
--- a/src/pretix/base/models/event.py
+++ b/src/pretix/base/models/event.py
@@ -415,7 +415,7 @@ class Event(EventMixin, LoggedModel):
             return super().presale_has_ended
 
     def delete_all_orders(self, really=False):
-        from .orders import OrderRefund, OrderPayment, OrderPosition, OrderFee
+        from .orders import OrderFee, OrderPayment, OrderPosition, OrderRefund
 
         if not really:
             raise TypeError("Pass really=True as a parameter.")
@@ -502,8 +502,10 @@ class Event(EventMixin, LoggedModel):
         ), tz)
 
     def copy_data_from(self, other):
-        from . import ItemAddOn, ItemCategory, Item, Question, Quota, ItemMetaValue
         from ..signals import event_copy_data
+        from . import (
+            Item, ItemAddOn, ItemCategory, ItemMetaValue, Question, Quota,
+        )
 
         self.plugins = other.plugins
         self.is_public = other.is_public
@@ -1183,8 +1185,8 @@ class RequiredAction(models.Model):
         created = not self.pk
         super().save(*args, **kwargs)
         if created:
-            from .log import LogEntry
             from ..services.notifications import notify
+            from .log import LogEntry
 
             logentry = LogEntry.objects.create(
                 content_object=self,
diff --git a/src/pretix/base/models/log.py b/src/pretix/base/models/log.py
index bba31273f..b37c6fa95 100644
--- a/src/pretix/base/models/log.py
+++ b/src/pretix/base/models/log.py
@@ -75,7 +75,10 @@ class LogEntry(models.Model):
 
     @cached_property
     def display_object(self):
-        from . import Order, Voucher, Quota, Item, ItemCategory, Question, Event, TaxRule, SubEvent
+        from . import (
+            Event, Item, ItemCategory, Order, Question, Quota, SubEvent,
+            TaxRule, Voucher,
+        )
 
         try:
             if self.content_type.model_class() is Event:
diff --git a/src/pretix/base/models/orders.py b/src/pretix/base/models/orders.py
index 8d64eac1d..44f044e39 100644
--- a/src/pretix/base/models/orders.py
+++ b/src/pretix/base/models/orders.py
@@ -209,7 +209,7 @@ class Order(LockModel, LoggedModel):
         return self.full_code
 
     def gracefully_delete(self, user=None, auth=None):
-        from . import Voucher, GiftCard, GiftCardTransaction
+        from . import GiftCard, GiftCardTransaction, Voucher
 
         if not self.testmode:
             raise TypeError("Only test mode orders can be deleted.")
@@ -838,7 +838,9 @@ class Order(LockModel, LoggedModel):
                          only be attached for this position and child positions, the link will only point to the
                          position and the attendee email will be used if available.
         """
-        from pretix.base.services.mail import SendMailException, mail, render_mail, TolerantDict
+        from pretix.base.services.mail import (
+            SendMailException, TolerantDict, mail, render_mail,
+        )
 
         if not self.email:
             return
@@ -1421,7 +1423,9 @@ class OrderPayment(models.Model):
         :type mail_text: str
         :raises Quota.QuotaExceededException: if the quota is exceeded and ``force`` is ``False``
         """
-        from pretix.base.services.invoices import generate_invoice, invoice_qualified
+        from pretix.base.services.invoices import (
+            generate_invoice, invoice_qualified,
+        )
 
         with transaction.atomic():
             locked_instance = OrderPayment.objects.select_for_update().get(pk=self.pk)
@@ -2066,7 +2070,9 @@ class OrderPosition(AbstractPosition):
         :param sender: Custom email sender.
         :param attach_tickets: Attach tickets of this order, if they are existing and ready to download
         """
-        from pretix.base.services.mail import SendMailException, mail, render_mail
+        from pretix.base.services.mail import (
+            SendMailException, mail, render_mail,
+        )
 
         if not self.attendee_email:
             return
diff --git a/src/pretix/base/models/organizer.py b/src/pretix/base/models/organizer.py
index beb12e7a2..58631fa7b 100644
--- a/src/pretix/base/models/organizer.py
+++ b/src/pretix/base/models/organizer.py
@@ -113,7 +113,7 @@ class Organizer(LoggedModel):
             ), tz)
 
     def allow_delete(self):
-        from . import Order, Invoice
+        from . import Invoice, Order
         return (
             not Order.objects.filter(event__organizer=self).exists() and
             not Invoice.objects.filter(event__organizer=self).exists() and
diff --git a/src/pretix/base/models/seating.py b/src/pretix/base/models/seating.py
index 351d67fdf..a494796e3 100644
--- a/src/pretix/base/models/seating.py
+++ b/src/pretix/base/models/seating.py
@@ -163,7 +163,7 @@ class Seat(models.Model):
     @classmethod
     def annotated(cls, qs, event_id, subevent, ignore_voucher_id=None, minimal_distance=0,
                   ignore_order_id=None, ignore_cart_id=None, distance_only_within_row=False):
-        from . import Order, OrderPosition, Voucher, CartPosition
+        from . import CartPosition, Order, OrderPosition, Voucher
 
         vqs = Voucher.objects.filter(
             event_id=event_id,
diff --git a/src/pretix/base/pdf.py b/src/pretix/base/pdf.py
index 177701dca..d4813fee1 100644
--- a/src/pretix/base/pdf.py
+++ b/src/pretix/base/pdf.py
@@ -544,7 +544,7 @@ class Renderer:
                 with open(os.path.join(d, 'out.pdf'), 'rb') as f:
                     return BytesIO(f.read())
         else:
-            from PyPDF2 import PdfFileWriter, PdfFileReader
+            from PyPDF2 import PdfFileReader, PdfFileWriter
             buffer.seek(0)
             new_pdf = PdfFileReader(buffer)
             output = PdfFileWriter()
diff --git a/src/pretix/control/forms/__init__.py b/src/pretix/control/forms/__init__.py
index 396944fb1..6bfef9e8b 100644
--- a/src/pretix/control/forms/__init__.py
+++ b/src/pretix/control/forms/__init__.py
@@ -10,6 +10,7 @@ from django.forms.utils import from_current_timezone
 from django.utils.translation import gettext_lazy as _
 
 from ...base.forms import I18nModelForm
+
 # Import for backwards compatibility with okd import paths
 from ...base.forms.widgets import (  # noqa
     DatePickerWidget, SplitDateTimePickerWidget, TimePickerWidget,
diff --git a/src/pretix/control/forms/event.py b/src/pretix/control/forms/event.py
index 1861ef1c0..e60aa51ba 100644
--- a/src/pretix/control/forms/event.py
+++ b/src/pretix/control/forms/event.py
@@ -1,3 +1,5 @@
+from urllib.parse import urlencode, urlparse
+
 from django import forms
 from django.conf import settings
 from django.core.exceptions import ValidationError
@@ -15,7 +17,6 @@ from i18nfield.forms import (
     I18nForm, I18nFormField, I18nFormSetMixin, I18nTextarea, I18nTextInput,
 )
 from pytz import common_timezones, timezone
-from urllib.parse import urlencode, urlparse
 
 from pretix.base.channels import get_all_sales_channels
 from pretix.base.email import get_available_placeholders
diff --git a/src/pretix/multidomain/urlreverse.py b/src/pretix/multidomain/urlreverse.py
index 707cfdaed..43ae4548d 100644
--- a/src/pretix/multidomain/urlreverse.py
+++ b/src/pretix/multidomain/urlreverse.py
@@ -91,7 +91,9 @@ def eventreverse(obj, name, kwargs=None):
         needed.
     :returns: An absolute URL (including scheme and host) as a string
     """
-    from pretix.multidomain import event_domain_urlconf, organizer_domain_urlconf, maindomain_urlconf
+    from pretix.multidomain import (
+        event_domain_urlconf, maindomain_urlconf, organizer_domain_urlconf,
+    )
 
     c = None
     if not kwargs:
diff --git a/src/pretix/plugins/badges/exporters.py b/src/pretix/plugins/badges/exporters.py
index eda15a118..1c5f4e4bf 100644
--- a/src/pretix/plugins/badges/exporters.py
+++ b/src/pretix/plugins/badges/exporters.py
@@ -121,7 +121,7 @@ OPTIONS = OrderedDict([
 
 
 def render_pdf(event, positions, opt):
-    from PyPDF2 import PdfFileWriter, PdfFileReader
+    from PyPDF2 import PdfFileReader, PdfFileWriter
     Renderer._register_fonts()
 
     renderermap = {
diff --git a/src/pretix/plugins/banktransfer/mt940import.py b/src/pretix/plugins/banktransfer/mt940import.py
index 56b04130a..a60440e9b 100644
--- a/src/pretix/plugins/banktransfer/mt940import.py
+++ b/src/pretix/plugins/banktransfer/mt940import.py
@@ -5,7 +5,6 @@ import mt940
 
 from pretix.base.decimal import round_decimal
 
-
 """
 The parse_transaction_details and join_reference functions are
 Copyright (c) 2017 Nicole Klünder
diff --git a/src/pretix/plugins/reports/exporters.py b/src/pretix/plugins/reports/exporters.py
index 388a01f67..9a051677b 100644
--- a/src/pretix/plugins/reports/exporters.py
+++ b/src/pretix/plugins/reports/exporters.py
@@ -43,8 +43,8 @@ class ReportlabExportMixin:
 
     @staticmethod
     def register_fonts():
-        from reportlab.pdfbase.ttfonts import TTFont
         from reportlab.pdfbase import pdfmetrics
+        from reportlab.pdfbase.ttfonts import TTFont
 
         pdfmetrics.registerFont(TTFont('OpenSans', finders.find('fonts/OpenSans-Regular.ttf')))
         pdfmetrics.registerFont(TTFont('OpenSansIt', finders.find('fonts/OpenSans-Italic.ttf')))
@@ -56,8 +56,8 @@ class ReportlabExportMixin:
         return BaseDocTemplate
 
     def create(self, form_data):
-        from reportlab.platypus import PageTemplate
         from reportlab.lib.units import mm
+        from reportlab.platypus import PageTemplate
 
         with tempfile.NamedTemporaryFile(suffix=".pdf") as f:
             Report.register_fonts()
@@ -162,8 +162,8 @@ class OverviewReport(Report):
         return pagesizes.landscape(pagesizes.A4)
 
     def get_story(self, doc, form_data):
-        from reportlab.platypus import Paragraph, Spacer, TableStyle, Table
         from reportlab.lib.units import mm
+        from reportlab.platypus import Paragraph, Spacer, Table, TableStyle
 
         if form_data.get('date_from'):
             form_data['date_from'] = parse(form_data['date_from'])
@@ -334,8 +334,8 @@ class OrderTaxListReportPDF(Report):
         return pagesizes.landscape(pagesizes.A4)
 
     def get_story(self, doc, form_data):
-        from reportlab.platypus import Paragraph, Spacer, TableStyle, Table
         from reportlab.lib.units import mm
+        from reportlab.platypus import Paragraph, Spacer, Table, TableStyle
 
         headlinestyle = self.get_style()
         headlinestyle.fontSize = 15
diff --git a/src/pretix/plugins/stripe/signals.py b/src/pretix/plugins/stripe/signals.py
index b4a94b98f..ddccc9205 100644
--- a/src/pretix/plugins/stripe/signals.py
+++ b/src/pretix/plugins/stripe/signals.py
@@ -21,8 +21,9 @@ from pretix.presale.signals import html_head
 @receiver(register_payment_providers, dispatch_uid="payment_stripe")
 def register_payment_provider(sender, **kwargs):
     from .payment import (
-        StripeSettingsHolder, StripeCC, StripeGiropay, StripeIdeal, StripeAlipay, StripeBancontact,
-        StripeSofort, StripeEPS, StripeMultibanco, StripePrzelewy24, StripeWeChatPay
+        StripeAlipay, StripeBancontact, StripeCC, StripeEPS, StripeGiropay,
+        StripeIdeal, StripeMultibanco, StripePrzelewy24, StripeSettingsHolder,
+        StripeSofort, StripeWeChatPay,
     )
 
     return [
diff --git a/src/pretix/plugins/ticketoutputpdf/ticketoutput.py b/src/pretix/plugins/ticketoutputpdf/ticketoutput.py
index 91f1d3c43..7a243e510 100644
--- a/src/pretix/plugins/ticketoutputpdf/ticketoutput.py
+++ b/src/pretix/plugins/ticketoutputpdf/ticketoutput.py
@@ -116,8 +116,8 @@ class PdfTicketOutput(BaseTicketOutput):
         return 'order%s%s.pdf' % (self.event.slug, order.code), 'application/pdf', outbuffer.read()
 
     def _create_canvas(self, buffer):
-        from reportlab.pdfgen import canvas
         from reportlab.lib import pagesizes
+        from reportlab.pdfgen import canvas
 
         # Doesn't matter as we'll overpaint it over a background later
         pagesize = pagesizes.A4
diff --git a/src/setup.cfg b/src/setup.cfg
index a112b0408..00dc9a4f1 100644
--- a/src/setup.cfg
+++ b/src/setup.cfg
@@ -8,9 +8,11 @@ max-complexity = 11
 combine_as_imports = true
 include_trailing_comma = true
 known_first_party = pretix
-known_third_party = versions
+known_third_party = versions,tests
 extra_standard_library = typing,enum,mimetypes
 multi_line_output = 5
+line_length = 79
+honor_noqa = true
 skip = make_testdata.py,wsgi.py,bootstrap,celery_app.py,pretix/settings.py,tests/settings.py,pretix/testutils/settings.py
 
 [tool:pytest]
diff --git a/src/tests/testdummy/signals.py b/src/tests/testdummy/signals.py
index 838818e96..559998d20 100644
--- a/src/tests/testdummy/signals.py
+++ b/src/tests/testdummy/signals.py
@@ -15,7 +15,10 @@ def register_ticket_outputs(sender, **kwargs):
 
 @receiver(register_payment_providers, dispatch_uid="payment_dummy")
 def register_payment_provider(sender, **kwargs):
-    from .payment import DummyPaymentProvider, DummyFullRefundablePaymentProvider, DummyPartialRefundablePaymentProvider
+    from .payment import (
+        DummyFullRefundablePaymentProvider,
+        DummyPartialRefundablePaymentProvider, DummyPaymentProvider,
+    )
     return [DummyPaymentProvider, DummyFullRefundablePaymentProvider, DummyPartialRefundablePaymentProvider]