Alize Cornet got the French off to a winning start in their final Group B match, overcoming an injury scare to beat Anabel Medina Garrigues 6-2 6-2.
And Jo-Wilfried Tsonga gave the third seeds an unassailable 2-0 lead in the tie with a battling 6-4 6-7 (7/9) 6-2 victory over Daniel Munoz-De La Nava.
The French duo then teamed up to win the mixed doubles, sending them through to Saturday's final in confident mood.
There they will face the Polish pairing of Agnieszka Radwanska and Grzegorz Panfil, who topped Group A with victory over Australia on Thursday.
In Friday's other match, the Czech Republic pairing of Radek Stepanek and Petra Kvitova finished their campaign on a winning note against the United States, whose challenge was ended by injuries to both John Isner and Sloane Stephens.