diff --git a/flax/nnx/filterlib.py b/flax/nnx/filterlib.py
index 824eb4315..e96d5ebc6 100644
--- a/flax/nnx/filterlib.py
+++ b/flax/nnx/filterlib.py
@@ -52,7 +52,7 @@ def to_predicate(filter: Filter) -> Predicate:
   elif isinstance(filter, (list, tuple)):
     return Any(*filter)
   else:
-    raise TypeError(f'Invalid collection filter: {filter:!r}. ')
+    raise TypeError(f'Invalid collection filter: {filter!r}. ')
 
 def filters_to_predicates(
   filters: tp.Sequence[Filter],
diff --git a/flax/nnx/variablelib.py b/flax/nnx/variablelib.py
index 8268c0651..8fa8f39a8 100644
--- a/flax/nnx/variablelib.py
+++ b/flax/nnx/variablelib.py
@@ -2292,8 +2292,8 @@ def variable_name_from_type(
   name = typ.__name__
   if name in VariableTypeCache:
     raise ValueError(
-      'Name {name} is already registered in the registry as {VariableTypeCache[name]}. '
-      'It cannot be linked with this type {typ}.'
+      f'Name {name} is already registered in the registry as {VariableTypeCache[name]}. '
+      f'It cannot be linked with this type {typ}.'
     )
   register_variable_name(name, typ)
   return name