alexandre is absolutely right, it's the Sud-Ouest (precisely: SNCASO) SO-M.2 scale model test aircraft for the SO.4000 experimental jet bomber.
There's been another unpowered glider scale testbed called "M.1" before which, interestingly, had been launched from the top of the only ever built and flown Heinkel He 274 4-engine high altitude bomber project aircraft derived from the He 177.
This is the M.1 mounted on the He 274:
And this is the final project, the SO.4000 "Vautour I":
Wikipedia about it for thouse who are interested:
https://en.wikipedia.org/wiki/SNCASO_SO.4000And another good page about it, but in russian:
http://www.airwar.ru/enc/xplane/so4000.htmlYour turn alexandre!
Best regards - Mike