Hard to say. According to one of my acquaintances who is quite obsessed with his SC, the SC could have either MAFAC CPs or Campag sidepulls starting ca 1969. It would appear this one came with the Campag as there is no CP brake cable stop at the rear. They were rather prominent. The stem is no help to me as I believe it is a replacement. Models from 69 and 70 would have Cinelli stems or Pivo. A 1971 bike would have either a Pivo stem or a 3TTT with a blank face clamping bolt and a conventional nut. The Campag brake models would have the 3TTT, MAFAC models would have the Pivo. But my own experience blow that correlation out of the water. My SC had a Pivo stem and Camapg brakes. This one also has Tipo hubs, which I think support 1969 to early 70s. But then my own SC had Record hubs. I believe they were original, but only the PO knows and he is no longer available. Of course all this is based on one person's experience.

It's French....what more can you say?

EDIT: Another clue is the remains of the 531 decal. Very early 70s. IIRC, this decal disappeared because the wording implied the forks and stays were butted also.