diff --git a/src/pip/_internal/locations/__init__.py b/src/pip/_internal/locations/__init__.py
index 7d5491d20ad..418b9607d20 100644
--- a/src/pip/_internal/locations/__init__.py
+++ b/src/pip/_internal/locations/__init__.py
@@ -65,7 +65,9 @@ def _looks_like_bpo_44860() -> bool:
 def _looks_like_red_hat_patched_platlib_purelib(scheme: Dict[str, str]) -> bool:
     platlib = scheme["platlib"]
     if "/$platlibdir/" in platlib and hasattr(sys, "platlibdir"):
-        platlib = platlib.replace("/$platlibdir/", f"/{sys.platlibdir}/")
+        platlib = platlib.replace(
+            "/$platlibdir/", f"/{sys.platlibdir}/"  # type: ignore
+        )
     if "/lib64/" not in platlib:
         return False
     unpatched = platlib.replace("/lib64/", "/lib/")