Here are five new signings who could have a significant impact on the upcoming Top 14 campaign:
Taniela Tupou (Racing 92)
The 29-year-old Australia prop will join Racing 92's rebuild after the Rugby Championship.
Tupou, described as "an Australian pit bull with hands like a fairy" by sports newspaper L'Equipe, will compete with another hulking prop in Demba Bamba for the starting tight-head shirt in Paris as Patrice Collazo begins his first full season as head coach.
Tupou said when he was signed in July he had been struggling with mental health issues brought on by the pressure of international rugby, before earning a Wallaby recall and impressing during the British and Irish Lions tour and starting in the Rugby Championship.
Tupou is one of two stand-out names to arrive at Racing alongside rugby league convert Joseph Manu after Owen Farrell's acrimonious departure during the summer.
Jordan Petaia (Perpignan)
The 31-time capped Australian returns to rugby from the Los Angeles Chargers where he spent a year on the NFL's International Player Pathway programme.
The talented 25-year-old, who can play across the back-line, will be looking to return to the Australia squad, with a home Rugby World Cup on the horizon in 2027 and head coach Joe Schmidt now able to select foreign-based players.
Nolann Le Garrec (La Rochelle)
The fleet-footed scrum-half moved from Racing 92 to Ronan O'Gara's La Rochelle.
He stood out during France's three Test defeats by New Zealand in July and with others injured has a chance to cement his place in the national team.
Antoine Dupont will miss France's November Tests against South Africa, Fiji and Australia with a long-term knee injury while Maxime Lucu is a doubt with a thumb problem.
Le Garrec joins an ageing La Rochelle squad which has also been boosted by fellow 23-year-old and Georgia full-back Davit Niniashvili.
Jiuta Wainiqolo (Lyon)
The 26-year-old winger switches to Lyon in a surprise move after scoring 11 tries for Toulon last season.
The Tokyo Olympic gold medallist has been one of the league's most dangerous finishers since arriving at Stade Felix Mayol four years ago.
He will be joined in the Lyon back-line by compatriot Iosefo Masi, who replaces another Fijian, Semi Radradra, after the centre's move to Japan.
Ignacio Brex (Toulon)
Toulon, three-time Champions Cup winners, needed a replacement for New Zealand-bound Leicester Fainga'anuku and turned to 33-year-old Italy centre Brex.
The 46-time international has formed a solid partnership with Tommaso Menoncello with the Azzurri and will add experience and an efficient defensive game to Toulon's attempt to win a first Top 14 title since Jonny Wilkinson's final season 11 years ago.