The 29-year-old Frenchman, who initially joined the club on a week's trial after a recommendation from French international Thomas Castaignède, has made good progress within the squad and capped his first starting appearance with a try.
Saracens head coach Rod Kafer said: "Initially, Denis came to us on a week's trial and we extended that to a month after his first appearance against Penzance.
"He started his first game against Rotherham and showed, like he has in training, that he has pace and power and reads the game well and is able to cover both the wing and centre positions."
