Of course, we avoid posting images that infringe on public morality or that condone violence. But the censorship of advertising posters is not to be decided by the arbitrary power of the owner or operator of the advertising space where they are displayed. Like all companies, we must comply with the principle of freedom of expression, as defined by the legislation in force.
As long as an advertisement has not been banned and does not violate the regulations laid down in the new penal code, nothing and no one can oppose their posting.
If RATP were to refuse, advertisers could simply take us to court for refusing to sell advertising space, and have us condemned to pay damages and interest.