Solution message:

Code certitude : PALAISROYAL

https://www.jigidi.com/solve/k2qx3u7b/paris-2/

Solving that second puzzle gives:

Code certitude : SEINEORSAY

https://www.jigidi.com/solve/72r3h1kz/paris-3/

Solving that third puzzle gives:

Code certitude : SALVADORDALI

https://www.jigidi.com/solve/7ke9n5ox/paris-4/

Solving that fourth puzzle gives:

Code certitude : GALERIEDELEVOLUTION

https://www.jigidi.com/solve/d8ay7f7k/paris-5/

Solving that fifth puzzle gives:

Code certitude : ANTENNERADIO

https://www.jigidi.com/solve/5f9ex78w/paris-6/

Soling that sixth puzzle, which is ludicrously easy compared to all the rest (only 36 pieces rather than 540!) gives:

Code certitude : CHOCOLATINE

Joining all those codewords by semicolons and entering them into https://www.certitudes.org/certitude?wp=GCA5JNG gives:

N 48 51.166 E 002 18.884

Phew!