Then it's probably time for a new guide rod. Given your location, getting one may be an issue as the parts are no longer available from S&W. However, someone may have one in France or they may have started making them locally. Possibly a local machinist or gunsmith might be able to face cut the flange and restore the sharp edge needed to hold it in place.
Numrich/Gun Parts Incorporated in the US will probably have them, I don't know about possible export/import restrictions.