The grid pattern I created in Adobe Photoshop and the spiral was something I found online and then modified for my needs. The same type thing could be created in many photo editing programs (GIMP is free) and even in vector programs like Illustrator or Inkscape (also free).
You can also make depth maps using 3D software. There are various methods of doing this and some experimentation has been done and shared on this forum. Tutorial - Creating a Depth Map from a 3D Model for 3D Engraving!
There have also been some experimentation making depth maps from physical objects. Thinking out of the bottle!
The French side of my family is quite a few generations back. We have visited Paris and look forward to exploring more of France.