diff --git a/photonai/processing/photon_folds.py b/photonai/processing/photon_folds.py
index c751cfc3..4bad2d33 100644
--- a/photonai/processing/photon_folds.py
+++ b/photonai/processing/photon_folds.py
@@ -26,7 +26,8 @@ def data_overview(y):
             return {}
         else:
             unique, counts = np.unique(y, return_counts=True)
-            unique = [str(u) for u in unique]
+            # replacing is necessary for float inputs, because mongoDB does not allow '.'-char
+            unique = [str(u).replace(".", "_") for u in unique]
             counts = [int(c) for c in counts]
             return dict(zip(unique, counts))
 
@@ -64,7 +65,7 @@ def generate_folds(cv_strategy, X, y, kwargs, eval_final_performance=True, test_
                     data_test_cases = cv_strategy.split(X, groups)
                 except:
                     logger.error("Could not stratify data for outer cross validation according to "
-                                   "group variable")
+                                 "group variable")
             else:
                 data_test_cases = cv_strategy.split(X, y)
 
diff --git a/test/processing_tests/test_results_handler.py b/test/processing_tests/test_results_handler.py
index bf44b97d..8c2793bb 100644
--- a/test/processing_tests/test_results_handler.py
+++ b/test/processing_tests/test_results_handler.py
@@ -305,3 +305,11 @@ def test_get_performance_table(self):
 
     def test_get_methods(self):
         self.hyperpipe.results_handler.get_methods()
+
+    def test_float_labels_with_mongo(self):
+        """
+        This test was added for a bug with float labels and saving to mongoDB.
+        """
+        local_y = self.__y.astype(float)
+        self.hyperpipe.output_settings.mongodb_connect_url = self.mongodb_path
+        self.hyperpipe.fit(self.__X, local_y)
\ No newline at end of file