Louw, 35, was part of Rassie Erasmus’ 2019 World Cup-winning squad and he announced his retirement from Test rugby soon after the tournament.
The South African back row revealed last week the end of the current Gallagher Premiership season at Bath will herald his retirement at the age of 35.
Bath's Springbok flanker has made 134 starts in 140 appearances with the English club and is quitting after playing nine seasons in the Premiership.
Harlequins' head of rugby Paul Gustard praised Joe Marler’s “street-savviness” as the England prop returned to help his club defeat Bath in the Heineken Champions Cup.
Veteran Springbok flanker Francois Louw is preparing for the third World Cup in his career, having been apart of the 2011 and 2015 campaigns.
Francois Louw's future at Bath Rugby seems anything but clear, with the club admitting they've yet to make a decision on the Springbok openside.
Francois Louw has now been cited having allegedly made contact with the eyes of Marco Fuser, during Baths win over Treviso on Saturday.
While Bath struggled in spells during their match against Benetton on Saturday, they did come away with a comfortable win.