A hospital in the Alpine city of Gap says the 70-year-old fell ill before a concert Thursday at a jazz festival in the French town of Barcelonnette.
Hospital official Maurice Marchetti said the Grammy Award winner is still in the intensive care unit Friday and his condition is "worrisome."
Jarreau, who started out in jazz before crossing over into pop and R&B, is in the midst of a European tour. It is unclear whether he will be able to make other stops planned for July, in Germany, Azerbaijan, Austria and Slovakia.
