Hello! Please have a look on https://www.osm.org/node/12302201502 (one of may nodes). What is the mean of the tags
FR-BRE-Star:stop_id = 6-4746
FR-BRE-Star:stop_name = Martigné
?
Did you mean 
gtfs:stop_id:FR-BRE-Star= 6-4746
gtfs:stop_name:FR-BRE-Star= Martigné
?