Le Club Accorhotels members can earn 500 bonus points when staying at a participating Mercure property in the UK and Ireland.
The "Mercure Early Booker" promotion applies to stays between April 3 and September 6 that are booked at least 30 days in advance by June 22.
Members must make their booking on either accorhotels.com, a "participating brands website" or via an Accor call centre.
A loyalty card number or member number must be used when making the reservation and the card presented at check-in.
The offer is available to all Le Club Accorhotels members, regardless of their status.
Accor has more than 70 Mercure hotels in the UK and Ireland. A Mercure has just opened near London Heathrow airport (see news, March 30).