Welcome to the Forum FreedomSeat.
Many countries including France have included the names
of designers and engravers somewhere on the stamp.
Many countries such as Austria, Denmark,Norway, Sweden,
Czechoslovakia and some others have usually placed
the designer's name on the lower left border
engraver on the right
. If the engraver was also the designer
then sometimes they place the name in the middle of the
France and Belgium in the past have placed the designers and
engravers names somewhere in image itself, sometimes only
Czechoslovakian engravers in the nineteen thirties would
hide their initials somewhere in the stamp vignette which
makes it fun finding them.
The forum has a sub forum which is strictly about engravers
and engraved stamps and going through the threads will answer
some of your questions.http://goscf.com/f/59
Since you are interested in French stamps there is a thread
about French engravers and also separate threads showing the
work of individual engravers.http://goscf.com/t/61565&whichpage=1http://goscf.com/t/61308http://goscf.com/t/61297