diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 3013edc0..33bca366 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -24,7 +24,6 @@ jobs:
         run: make flake8
 
       - name: check source code formatting
-        continue-on-error: true
         run: make black
 
       - name: type check the source code
diff --git a/breathe/directives/function.py b/breathe/directives/function.py
index e35d21cf..b47b531a 100644
--- a/breathe/directives/function.py
+++ b/breathe/directives/function.py
@@ -253,11 +253,11 @@ def _resolve_function(self, matches, args: Optional[cpp.ASTParametersQualifiers]
         res = []
         candSignatures = []
         for entry in matches:
-            text_options = {"no-link": u"", "outline": u""}
+            text_options = {"no-link": "", "outline": ""}
 
             # Render the matches to docutils nodes
             target_handler = create_target_handler(
-                {"no-link": u""}, project_info, self.state.document
+                {"no-link": ""}, project_info, self.state.document
             )
             filter_ = self.filter_factory.create_outline_filter(text_options)
             mask_factory = MaskFactory({"param": NoParameterNamesMask})
diff --git a/breathe/renderer/sphinxrenderer.py b/breathe/renderer/sphinxrenderer.py
index 978299fb..cae3a57b 100644
--- a/breathe/renderer/sphinxrenderer.py
+++ b/breathe/renderer/sphinxrenderer.py
@@ -1681,7 +1681,7 @@ def visit_verbatim(self, node) -> List[Node]:
             text = node.text.replace("embed:rst:inline", "", 1)
         else:
             # Remove the first line which is "embed:rst[:leading-asterisk]"
-            text = "\n".join(node.text.split(u"\n")[1:])
+            text = "\n".join(node.text.split("\n")[1:])
 
             # Remove starting whitespace
             text = textwrap.dedent(text)
diff --git a/documentation/source/conf.py b/documentation/source/conf.py
index 29834090..9f81ce65 100644
--- a/documentation/source/conf.py
+++ b/documentation/source/conf.py
@@ -143,8 +143,8 @@
 master_doc = "index"
 
 # General information about the project.
-project = u"Breathe"
-copyright = u"2009-2014, Michael Jones"
+project = "Breathe"
+copyright = "2009-2014, Michael Jones"
 
 
 # The language for content autogenerated by Sphinx. Refer to documentation
diff --git a/requirements/development.txt b/requirements/development.txt
index 69363b23..c1b74992 100644
--- a/requirements/development.txt
+++ b/requirements/development.txt
@@ -7,4 +7,4 @@ pytest
 mypy>=0.900
 types-docutils>=0.17.0
 
-black
+black==22.1.0
diff --git a/tests/test_renderer.py b/tests/test_renderer.py
index 2b9a5860..16889818 100644
--- a/tests/test_renderer.py
+++ b/tests/test_renderer.py
@@ -315,7 +315,7 @@ def test_render_func(app):
         argsstring="(int)",
         virt="non-virtual",
         param=[
-            WrappedParam(type_=WrappedLinkedText(content_=[WrappedMixedContainer(value=u"int")]))
+            WrappedParam(type_=WrappedLinkedText(content_=[WrappedMixedContainer(value="int")]))
         ],
     )
     signature = find_node(render(app, member_def), "desc_signature")
@@ -460,7 +460,7 @@ def test_render_variable_initializer(app):
         definition="const int EOF",
         type_="const int",
         name="EOF",
-        initializer=WrappedMixedContainer(value=u"= -1"),
+        initializer=WrappedMixedContainer(value="= -1"),
     )
     signature = find_node(render(app, member_def), "desc_signature")
     assert signature.astext() == "const int EOF = -1"
@@ -470,7 +470,7 @@ def test_render_define_initializer(app):
     member_def = WrappedMemberDef(
         kind="define",
         name="MAX_LENGTH",
-        initializer=WrappedLinkedText(content_=[WrappedMixedContainer(value=u"100")]),
+        initializer=WrappedLinkedText(content_=[WrappedMixedContainer(value="100")]),
     )
     signature_w_initializer = find_node(
         render(app, member_def, show_define_initializer=True), "desc_signature"
@@ -480,7 +480,7 @@ def test_render_define_initializer(app):
     member_def_no_show = WrappedMemberDef(
         kind="define",
         name="MAX_LENGTH_NO_INITIALIZER",
-        initializer=WrappedLinkedText(content_=[WrappedMixedContainer(value=u"100")]),
+        initializer=WrappedLinkedText(content_=[WrappedMixedContainer(value="100")]),
     )
 
     signature_wo_initializer = find_node(
diff --git a/tests/warnings/source/conf.py b/tests/warnings/source/conf.py
index 8c356c37..3dfc126d 100644
--- a/tests/warnings/source/conf.py
+++ b/tests/warnings/source/conf.py
@@ -55,8 +55,8 @@
 master_doc = "index"
 
 # General information about the project.
-project = u"Test Breathe Warnings"
-copyright = u"2014, Michael Jones"
+project = "Test Breathe Warnings"
+copyright = "2014, Michael Jones"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -209,8 +209,8 @@
     (
         "index",
         "TestBreatheWarnings.tex",
-        u"Test Breathe Warnings Documentation",
-        u"Michael Jones",
+        "Test Breathe Warnings Documentation",
+        "Michael Jones",
         "manual",
     ),
 ]
@@ -241,7 +241,7 @@
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
 man_pages = [
-    ("index", "testbreathewarnings", u"Test Breathe Warnings Documentation", [u"Michael Jones"], 1)
+    ("index", "testbreathewarnings", "Test Breathe Warnings Documentation", ["Michael Jones"], 1)
 ]
 
 # If true, show URL addresses after external links.
@@ -257,8 +257,8 @@
     (
         "index",
         "TestBreatheWarnings",
-        u"Test Breathe Warnings Documentation",
-        u"Michael Jones",
+        "Test Breathe Warnings Documentation",
+        "Michael Jones",
         "TestBreatheWarnings",
         "One line description of project.",
         "Miscellaneous",