Sadly not much more to add I'm afraid.
I discoved this car/photo at a classic car show in France last year. The French Lambert club had some images of various Lambert vehicles on a wall, including this one. I spoke to a Club member about the car, but he couldn't add much more information. He believed the car no longer existed, but its racing appearances were very limited in the early to mid-1960s. It was Germain Lambert's last vehicle project.