possibly one time promotion only
I spoke with a le Club guy this afternoon who asked his supervisor who in turn asked her higher-up. Their position is that this is a one-time promotion.
If you read the Aeroplan promotional text, you will not find the wording "per stay". It just says stay and earn 5000 miles. It does not say you can repeat it.
I am at my second stay at Novotel in Athens, but my first stay has not posted yet. I may switch to Miles and More once it posts.
With Miles and More, at least you know for sure you can earn 3500 miles per stay, for up to 10 stays. Personally I think Miles and More miles are more valuable than Aeroplan miles. Maybe 3500 Miles and More miles are almost worth the same as 5000 aeroplan miles.
The only thing is that a qualifying stay for Miles and More promotion is 1 night for Sofitel, 2 nights for Novotel, 4 nights for ibis. That's not a problem for me. I don't do 1 night stay, too much hassle. I don't stay at budget hotels like ibis either.