Victoria Chieche, 38, was last seen on July 20 after leaving the house.
She left her Mousseau Street home around 6 p.m. on her bike, without her wallet or any other belongings.
Const. Martin Simard with the Longueuil police department said authorities are actively looking for a man who she may have talked to.
"She went to a convenience store located on Périgny Street and Boulevard des Ormeaux in Old Longueuil Borough," Simard said. "We also know that she talked with a man — a man that she probably knew. We would like to trace the man."
Simard said the man is not a suspect and that police just want to speak with him to see if he has any information about Chieche's whereabouts.
Chieche weighs about 140 pounds and has red shoulder-length hair.
She was wearing a white t-shirt and shorts, with yellow running shoes.
Anyone with information should call Info-Crime at (514) 393-1133.