The Cottagers chief moved quickly to sign the 29-year-old Senegal international on a free transfer to help ease the injury crisis gripping the club with Simon Davies and Mahamadou Diarra both ruled out for several months, while Pajtim Kasami and Kerim Frei are struggling for fitness.
Tavares played under Jol during the Dutch tactician's time in charge of Hamburg, while he has experience of playing in England following a lengthy loan spell with Championship side Middlesbrough in the 2011-12 campaign.
On Tavares, who was a free agent having left Hamburg at the end of last season, Jol told the club's website: "Mickael is a typical holding midfielder and I'm delighted that we've been able to strengthen this area.
"He played for me when I was at Hamburg so I'm familiar with his qualities and he will prove to be a very good addition."
Tavares is also delighted to get an opportunity to ply his trade in the top tier of English football with the Cottagers.
He added: "I'm happy that I'm now officially a Fulham player and I'm looking forward to playing under Martin Jol once more.
"The players and staff have made me feel welcome and I can't wait to get started with my new teammates."