diff --git a/zmldapsync/zmldapsync.pl b/zmldapsync/zmldapsync.pl
index ac8b455..75ccd66 100644
--- a/zmldapsync/zmldapsync.pl
+++ b/zmldapsync/zmldapsync.pl
@@ -968,5 +968,10 @@ sub get_default_conf {
       }
     };
   }
+  # If some attribute mapping is defined in the provided conf
+  # do not use defaults
+  foreach my $type ( qw( users groups ) ) {
+    $defaults->{$type}->{attr_map} = {} if ( defined $conf->{$type}->{attr_map} );
+  }
   return merge $defaults, $conf;
 }