Loic Perrin's rough tackle in the 26th put Kylian Mbappe out of the game.
Paris St Germain's Neymar struck early to secure a 1-0 win over 10-man St Etienne as they claimed a record-extending 13th Coupe de France on Friday in a near empty stadium as French soccer came out of a four-month break due to the COVID-19 pandemic.
The Brazilian scored on the rebound in the 14th minute after PSG fellow forward Kylian Mbappe sprinted clear and saw his shot blocked by goalkeeper Jessy Moulin, with only 5,000 fans in the 80,000-seater Stade de France due to strict health protocols.
Earlier, French President Emmanuel Macron had met the players on the pitch but kept his distance and wore a face mask.
The atmosphere in the run-up to the first professional game in France after the long hiatus was far from festive with only a handful of people around the stadium before the match.
The contest got off to an eventful start with Yvann Macon felling Neymar in the opening seconds to earn a yellow card and St Etienne's Denis Bouanga hitting the post in the fifth minute.
But it was the Parisians who scored when Neymar pounced on Moulin's save to fire in.
Loic Perrin's rough tackle in the 26th put Mbappe out of the game. The St Etienne captain was sent off in his last game and four other players were booked as tempers briefly flared.
With Ligue 1 champions PSG chasing a quadruple of titles this season, the few fans in the stands breathed a sigh of relief when Mbappe returned on crutches to the bench after the interval, joking and laughing with his team mates.
"It went crack," Mbappe was heard telling Macron of his injury during the trophy ceremony. Macron then asked whether anything was broken and Mbappe said "No, I don't think so."
St Etienne kept finding ways into the PSG box even after going a man down but missed out on adding to their six Cup wins.
"We won the final and that is what matter," PSG coach Thomas Tuchel said.
His team had lost last year's final to Stade Rennes on penalties.
The German was also angry with the way St Etienne had played from the start.
"It was complicated with all the fouls to Thilo Kehrer, Neymar and Mbappe. In the last three matches against St Etienne they get a red card in the first 30 minutes. I don't know what is being said in their dressing room. It is horrible I can't understand it.
"We won and we have a lot of things to improve, to talk about and analyse," he said.