I did not know you had a Gitanes TDF.

Quill stems are raised by loosening the bolt on top of the stem and giving it a good whack with a mallet. When the bolt drops down, then the stem will loosen and you can adjust the up/down...side to side all you want.

While it is loose, pull it out and give it a little coating of grease. Prevents seizure.

If seized, report back.

Good luck!