Yes, it's obviously a repair, some of those rust spots are from welding splatter, which would never happen at the factory. On French bikes of this era, they would often have joints without enough filler for whatever reason. I always figured it was because the worker had trop de vin au déjeuner. Mixed weld/braze was very uncommon, although I suppose it's possible that was a spot weld to begin with. I'm not sure how easy it would be to find a good example.