Hi Bruno,
It is generally recomended that you have high school maths and physics and in fact some ground schools in the Uk ( and maybe even elsewhere) insist that you have them. However, not all do and it is also possible to do ground school ( theory exams) by distance learning. I personally know of at least one person who did not have either physics or maths at high school level and recently passed all 14 of his theory exams after doing the distance learning package from Bristol ground School. Hope this helps.
Willby