This comes probably from aFrench picture named " Un homme et une femme"
directed by Lelouch ( actors J.L. Trintignant and Anouck Aimé)
On the film Jean louis Trintignant act as a professional driver and on some sequences of this film he drives aMustang and a Gt 40
You can reconize him when the camera do a travelling inside a car
Just "Gougle" the tittle of this film ( you tube too) and you will retrieve the Mustang and the Gt 40
For your Info
J.L trintignant is the nephew of the well known former champion Maurice Trintignant
He drove many years after this famous film at le mans and on various French track cups
I remember checking out this DVD from Netflix years ago and before streaming became popular. It was in French but that was alright....all I wanted to hear were the cars anyway. I believe it was filmed in '66 and there was a sequel done in the 80's.