I don't know if the disks listed are legal but Windows XP supports more than 100 languages and dialects so any XP disk should work. A friend bought a used laptop with XP (English) and I set it up to Spanish (Guatemala), installed the Office language pack and it all worked out just fine.
Can you borrow a computer with XP to test? All you need is a person who reads French to change it back to English after the test.