You probably did something wrong somewhere, because the whole download instructions are in English, as over a 1000 downloads from the US have seen
Have you received any email confirmation of your puchase, with your activation code ? If not, the purchase did not go through, hence the reason you cannot donwload (the website is handled by a different company from us and I suppose they revert to French when they face a problem...

).
It may occur sometimes that some credit card are refused or blacklisted. Anything like this ?
If the trouble goes on, let send us a screenshot of your problem to
webmaster@ageod.com