I don't know, normally in Thailand you suppose to drive with a Thai or international, same for Malaysia, Malaysia recognized the Thai driving license but I don't know about the French
By the way if you have only a French driving license I don't know if you can get an insurance for Malaysia and for Thailand if you have a problem you will not be cover
No idea, I am not a tourist in Thailand , I am working so personally I can pass any number of times, it all depends on the officers , some let you go back and other may tell you to go to the embassy of the country you are coming