Nothing like a flight or stay to precipitate an offer too late to take advantage. I just got back from a business trip with an Accor stay, and wife and I received paper mail offers for 4x Delta SkyMiles for Accor stays.
Offer details here, open to new or existing account holders, book by 2/28, stay by 4/15.
Key step is you must update your Accor profile to automatic conversion to Delta SkyMiles.
Normally 2 Le Club Accorhotels points = 1 Skymile. 4x is better than most airline partners, but not as sweet as the 2:5 conversion for Iberia Avios, which can be freely converted to British Airways Avios, see full list of airline partners here. Update: from March 1, 2013 the transfer rate for Iberia Avios will drop to 1:1, still better than some other base rates but not as good as frequent promotions like this Delta one.
Note that “automatic conversion” is misleading as a minimum balance of 3,000 points is required to trigger a transfer. This is lower than the 4,000 points needed for a manual transfer.
The offer does not specify how the 4x is handled for stays that produce cumulative balances during the promotion of less than 3,000 points. For instance, will a stay of 500 base points produce 2,000 points that are not transferred to Delta and then be switched after the promotion to a different airline?
And it is not clear if existing balances are automatically converted to miles when account preferences are updated, so those with large Accor balances should confirm prior to switching their preferences.