When I was looking at Accor’s sale page for some properties in London, it had this box promoting 600 bonus points for those that sign up for the program.
You probably need to have a stay before these points post and the expiry of this offer is unclear.
You can access the sign up page for this offer here (box on the lower right corner).
Le Club Accorhotels occasionally has bonus points for new account sign ups. There is a 250 bonus points offer for one stay as well that should stack with this offer (+ all other regional offers).