Pau announced on Thursday that they have signed Toulon back-row Steffon Armitage on a three-year contract.
A statement on Pau's official website said the announcement was in the pipeline for several days already, but could not be confirmed as various documents needed for Armitage's transfer had not been validated by both parties.
But those issues have been sorted out and the 30-year-old, who has represented England in five Tests, will leave Toulon at the end of the 2015/16 season.
Armitage will be in familiar company at Pau as his former Toulon team-mate Carl Hayman is the club's forwards coach.
Armitage moved to Toulon from London Irish in 2011 and has been at the forefront of the Top 14 club's achievements for the past five years.
During that time the 30-year-old was named European Player of the Year in 2014 and he also won three consecutive European titles with Toulon from 2013 to 2015.