After the Total Film article about 'Bel Ami' release date, Bel Ami Film contacted Protagonist Pictures to check the "December 2011" date.
Protagonist Pictures' reply:
There’s no distributor attached to the film in the US as yet so therefore no release date. No confirmation on the UK yet either I’m afraid – we’ll post this info on our website as soon as there is a definite date. I think the ETA on Total Film is purely speculative at this stage.
ETA: According to Independent Films, the distributor for 'Bel Ami, the Dutch release date is February 17, 2011
Thanks to Brumbears for the Dutch date