Wow... I looked more carefully at the picture and you're right... They were probably part of a model, maybe for some dangerous or expensive scene they couldn't do at full scale (like the bridge scene from the first Superman movie, which was done with models).

On a French forum where I posted the pic, they say that there is a mix between scale models and full size cars, indeed some seem rather small compared to others (e.g. the Type H on the right)

Maybe we should search for Universal movies from that time that were set in France but filmed in the U.S., as those cars could be used in the background... I can't think of any particular film now, but could be.

Indeed, it is puzzling ...

I found this very interesting shot on Tumblr, tagged Universal Studios 1966:

In the back is a long row of abandoned/junked French cars and trucks, mostly Renaults and Citroens. I wonder what Universal production used so many of them?