Unlike in your country Armenia, in France sellers are under certain obligations before the customers, for example: they can't refuse to serve basic needs items like soap, condoms, cosmetics, refrigerators, etc.
As for the Chanel bags I was going to buy, unfortunately, they can because they belong to the luxury segment. So no, he can't put deadbolts because he registered as a seller and owns a website that he must maintain in accordance with the French laws.
And if we speak about that site in particular, the laws of Quebec, which aren't that different because they are an off-spring from France.