I would recommend to buy 50 shares, if you do not have direct access to French brokers.
I am personally a shareholder of Accor myself, but being based outside France, the transfer is way too difficult if you do not have direct access to French brokers.
It is a good investment btw, I think the share value has risen almost 50% from the time I bought it, and I do get some dividends yearly. Of course I wish Accor will continue to perform and roll out better benefits for Elite to get bigger market share from the big american hotel chain rivals.
Those who are based in Asia and able to visit SIN regularly can PM me, as I am able to help you purchase it from SIN.
(However, if you require au nominatif - for those trying for 1 Accor Share only, you may have to find a direct french broker.)