The Ligue 1 outfit have made a bid for the player and hope to conclude a loan deal with a view to a permanent switch.
Kapo currently has 18 months left on his contract at the DW Stadium, but he is down the pecking order under new boss Roberto Martinez - making just one substitute appearance this season.
The 29-year-old now believes his future will become a lot clearer this week, telling skysports.com: "It should be decided by Thursday. I will be in Boulogne to conclude everything, Thursday will be the D-Day for me.
"I need football time, I am not getting it here so it is time to move on.
"I still have 18 months on my contract here but that is life when you are not in the plans of a manager.
"But injuries did not help me as well, so it is not the fault of anyone, c'est la vie."