France coach Bernard Laporte has called up a group of 25 players to take part in a series of physical and psychological exercises ahead of their autumn Test matches.
Sixteen of the group will travel to Marcoussis on Monday and Tuesday, while the remaining nine will make the trip on Wednesday.
It is the second time Laporte has called up players for the specialist training, with a first series of exercises having taken place in August.
For that session, six players turned down the invitation, instead choosing to stay with their respective clubs for the start of the Top 14.
That decision infuriated Laporte, who threatened at the time not to call them up at all for the November tour.
However, five of the six absentees last month - Toulouse trio Jean-Baptiste Elissalde, Yannick Jauzion and Cedric Heyman and Biarritz's Damien Traille and Dimitri Yachvili - will be present in Marcoussis this week, while Stade Francais' Pieter de Villiers, who played against Perpignan on Sunday, will undergo the tests on September 12 and 13.
France will take on Australia on November 5 in Marseille, with a match against Canada in Nantes taking place a week later.
Clashes with Tonga in Toulouse and South Africa at the Stade de France will then follow.
Laporte is expected to announce his squad for the Tests by the end of October.
Saracens director of rugby Mark McCall believes Alex Lozowski has only just scratched the surface of his potential after the 23-year-old celebrated his England recognition by scoring a try-double against Bristol.