diff --git a/tryton/common/domain_parser.py b/tryton/common/domain_parser.py
index ccedb2d696..275d0184b2 100644
--- a/tryton/common/domain_parser.py
+++ b/tryton/common/domain_parser.py
@@ -1298,7 +1298,7 @@ class DomainParser(object):
                             operator = '='
                     if field['type'] in ('integer', 'float', 'numeric',
                             'datetime', 'date', 'time'):
-                        if value and '..' in value:
+                        if isinstance(value, str) and '..' in value:
                             lvalue, rvalue = value.split('..', 1)
                             lvalue = convert_value(field, lvalue, self.context)
                             rvalue = convert_value(field, rvalue, self.context)