diff --git a/backend/domain/simple_submission_checks/constraints/extension_not_present_constraint.py b/backend/domain/simple_submission_checks/constraints/extension_not_present_constraint.py
index 864cb750..1a5ddcbb 100644
--- a/backend/domain/simple_submission_checks/constraints/extension_not_present_constraint.py
+++ b/backend/domain/simple_submission_checks/constraints/extension_not_present_constraint.py
@@ -11,22 +11,22 @@
 
 class ExtensionNotPresentConstraint(BaseModel):
     type: ConstraintType = ConstraintType.EXTENSION_NOT_PRESENT
-    extension: str
+    not_present_extension: str
 
     def validate_constraint(self, path: Path) -> ExtensionNotPresentConstraintResult:
         directory = os.listdir(path)
 
-        files_with_extension = [file for file in directory if file.endswith(self.extension)]
+        files_with_extension = [file for file in directory if file.endswith(self.not_present_extension)]
 
         if files_with_extension:
             return ExtensionNotPresentConstraintResult(
-                extension=self.extension,
+                extension=self.not_present_extension,
                 is_ok=False,
                 files_with_extension=files_with_extension,
             )
 
         return ExtensionNotPresentConstraintResult(
-            extension=self.extension,
+            extension=self.not_present_extension,
             is_ok=True,
             files_with_extension=files_with_extension,
         )