This promotion has been running since the start of June, but I have only just picked it up – apologies!
Accor is the hotel group behind Novotel, Sofitel, Mercure, Ibis and M Gallery, amongst others. It is best known on Head for Points for its weird mileage transfer anomaly, whereby you get 0.5 Avios per point if you transfer them to British Airways, but 1 Avios per point if you transfer to Iberia (and then move them to BA!).
To qualify for the ‘triple points’ offer, you must select British Airways Executive Club as your earnings partner and book a 2-night minimum stay at any Accor brand. You do NOT have to register for the promotion.
As you can see here, the standard earning rate with Accor is 1 Avios per €1 (0.5 Avios per €1 at Ibis) so this becomes 3 per €1 (1.5 at Ibis). This is not a bad return, although remember that many hotel groups give a flat 500 Avios points per stay as their standard reward.
You would still need to spend at least €170 over two nights with Accor to earn 500 Avios – Carlson, Hyatt and Hilton give you 500 Avios per stay every day of the year, even for one-night stays.
(It is also worth reminding yourself of this more generous Mercure promotion, which offer 2,000 – 2,300 Avios for a Mercure stay over the Summer. This is definitely a decent deal.)