Alexander Frei has admitted he would consider a return to France despite only joining Borussia Dortmund in June.
The Swiss international has scored 13 goals in 28 games at Signal-Iduna-Park, but has failed to impress to the extent that he did during his time in Ligue 1 with Rennes.
Lens and Paris Saint Germain are both believed to be interested in the player who topped the French goalscoring charts in 2004/2005.
Whilst Frei insists he has heard nothing from PSG yet, he has refused to rule out a possible return to France in the summer.
"I have never been contacted by Paris," Frei told France Football.
"If that was the case, I would have to think about it quite seriously."
Lens are believed to be keen to partner Frei with Aruna Dindane as they prepare for a possible UEFA Champions league campaign next season.