diff --git a/app/scodoc/TrivialFormulator.py b/app/scodoc/TrivialFormulator.py
index 25442194f..1cf4ea924 100644
--- a/app/scodoc/TrivialFormulator.py
+++ b/app/scodoc/TrivialFormulator.py
@@ -254,13 +254,13 @@ class TF(object):
                 continue  # allowed empty field, skip
             # type
             typ = descr.get("type", "string")
-            if val != "" and val != None:
+            if val != "" and val is not None:
                 # check only non-null values
                 if typ[:3] == "int":
                     try:
                         val = int(val)
                         self.values[field] = val
-                    except:
+                    except ValueError:
                         msg.append(
                             "La valeur du champ '%s' doit être un nombre entier" % field
                         )
@@ -270,30 +270,24 @@ class TF(object):
                     try:
                         val = float(val.replace(",", "."))  # allow ,
                         self.values[field] = val
-                    except:
+                    except ValueError:
                         msg.append(
                             "La valeur du champ '%s' doit être un nombre" % field
                         )
                         ok = 0
-                if typ[:3] == "int" or typ == "float" or typ == "real":
-                    if (
-                        val != ""
-                        and val != None
-                        and "min_value" in descr
-                        and val < descr["min_value"]
-                    ):
+                if (
+                    ok
+                    and (typ[:3] == "int" or typ == "float" or typ == "real")
+                    and val != ""
+                    and val != None
+                ):
+                    if "min_value" in descr and self.values[field] < descr["min_value"]:
                         msg.append(
                             "La valeur (%d) du champ '%s' est trop petite (min=%s)"
                             % (val, field, descr["min_value"])
                         )
                         ok = 0
-
-                    if (
-                        val != ""
-                        and val != None
-                        and "max_value" in descr
-                        and val > descr["max_value"]
-                    ):
+                    if "max_value" in descr and self.values[field] > descr["max_value"]:
                         msg.append(
                             "La valeur (%s) du champ '%s' est trop grande (max=%s)"
                             % (val, field, descr["max_value"])