Update 10/05/21: Calendar_Gear_French_v2.stl
The months names are centered between the month marks instead of on the marks (seemed more logical to me for a calendar) But I kept the first file for those of you who don't agree with my logic ;)

Originally intended this as a simple make of the original thing, but I ended up modifying 2 important parts:

1) the calendar gear : the months are translated in French (many thanks to HackerJack42 for sharing the scad file !)
2) the finger wheel, with deeper holes and a turning arrow to show the right direction for the course of time. This was intended to be easier for young kids (my son is 5, my girl still a baby => less effort needed for small fingers)

I also hand-painted the planets with my son's help! :D

I was particularly careful about setting the planets and the Moon at their actual positions.
I also stuck a circular strip of paper on the base to use the Saturn arm as a year marker until 2030 (10 years / 122°) After that, I'll find another idea :D

Apart from my modded files, you may use all the files from the original thing below, which are just perfect :
https://www.thingiverse.com/thing:4632441

...And why is this written in English if my first concern was to translate the months for French speakers??!
Because if you can't read English, the process of printing the original parts + the assembly process will be hell! So I'm saving the French-only readers from a lot of pain and misery, they won't even read this! :D

I should add that the actual credit for this creation shall go to user Zippitybamba (https://www.thingiverse.com/thing:4613061) who made the original design and shared the scad code, thus allowing remixers to mod it at will. But I based my construction on the remix from user HackerJack42, so I don't know if my modded gears would work with the true original.