There were no injuries in the 2:30 a.m. attacks and only "limited" damage, with walls of two villas blackened by the explosion, according to the prefecture of the Pyrenees-Atlantic region in southwest France. A third small bomb failed to explode, the prefecture said.
There were no arrests, but authorities launched an investigation, officials said.
Ostape, the name of the resort made up of five villas, a spa and restaurant, is located in the verdant hills of the Basque country in southwest France, near the village of Bidarray.
The auberge-style resort was the target of two failed bomb attempts, in 2003 and 2004, before it opened.
There have been no claims of responsibility for any of the attempted attacks. However, the local press has questioned whether rocketing real estate prices in the region could have played a role.
Small attacks by Basque nationalists have been on the decline in recent years.