^^^^
I'll make a start
Grades 14-9 are regional club grades
Grades 8-5 are National grades (very good but not elite track)
Compulsory Levels 5 - 2 are elite track in age. You must pass level 2 to move up to Espoir, Junior, Senior Elite.
Levels 7-2 (and then Challenge) are county/regional levels, modified out of age FIG. Challenge is scored as FIG and there is a chance to move to National elite competitions if a certain level is reached.
Not sure about Novice, Intermediate etc as we don't have them here but I assume they are roughly the same as our county/regional levels above.
Each region decides there own requirements for these types of competitions. Grades are set by BG.
Then there is county and regional floor and vault competitions with different requirements again and some restrictions.
And then General Gymnastics have their own levels for non-artistic gymnasts where hours are restricted.
(The grades system used to 6-1 but that has changed now to 14-5)
Hope that helps