sitigeltfel,
I suspect its not Apple that's applying these restrictions, but it may rather be a byproduct of their content licensing deals with their suppliers that they have to make a reasonable attempt at establishing the correct jurisdiction of a purchaser.
Haven't tried this, but have you considered dissociating your credit card from your iTunes account and then subsequently trying to change the country of your account ?
Assuming this works, you will need to work around the payment issue by buying gift vouchers on your french card and applying these against your transaction (try with a nominal value first before undertaking any large orders !).