Help me ID the year of this car

This is a blowup of a 1/2 x 1/2-inch portion of a postcard I’m trying to date. The picture was taken in Luxembourg, and it seems that it could be anywhere from the 1960s to the 1970s. The car is the only thing that could help establish the earliest possible date of the photo.

My first reaction is that it is a Citroen, possibly a mid-70s DS?

Can anyone help me date it more precisely?

Almost positive you’re correct in that it’s a DS. But as far as I know the rear end looked the same from the '50s up to the end in 1975, so unless there’s some subtle tweaks only a Citroen enthusiast might spot, this one’s going to be tough to nail down.

It’s absolutely a DS (or an ID, which is a DS with simplified steering and brakes)) but there’s not enough detail to determine the year, or even if it’s a DS19 or a DS21.