Luftwaffe units involved in Rennes Railway yards raid, 17th June 1940?

[Laurent Rizzotti]

All French sources agree that the Rennes bombing was made by a small German formation that dropped only a few bombs, one hitting an ammunition train that blew up, killing many people in other trains parked around it.

This french webpage has a witness speaking of "3 German bombers, probably Do 17", and as also a video showing the results of the raid (German propaganda):
http://www.wiki-rennes.fr/Bombardement_du_17_juin_1940

But other witnesses said "3 Stuka", "3 fighter bombers", "5 bombers", etc...

I think the conclusion can only be that it was a small German formation that dropped only some bombs... and so it could be a part of any unit flying this day over Britanny against another target and that attacked these trains as an opportunity target. Or even a reconnaissance flight.