The referee then watched a VAR replay of a Neymar punch and showed him a straight red card.
As he left the pitch, the Brazilian told the fourth official he had heard a racist comment.
The game – which was watched by a crowd of about 5,000 fans at the Parc des Princes – was fractious even before that late brawl. There were 17 cards shown in total, a record for a Ligue 1 game in the 21st century.
A melee broke out, with Kurzawa and Amavi punching and kicking each other.
Benedetto and Paredes were each shown second yellow cards, with Kurzawa and Amavi shown straight reds.
A VAR review showed Neymar had punched the back of the head of Alvaro, a player he had been in a running battle with, and he was shown a straight red card – having earlier been booked.
Alvaro had also been involved in a big first-half flashpoint when he suggested Angel di Maria spat at him.
What about the game itself?
PSG – who lost 1-0 to promoted Lens on Thursday – have lost their opening two league games for the first time in 36 years. They finished 13th that season.
The last time they lost their first two games without scoring was 1978.
Including the Champions League final against Bayern Munich only 21 days ago, that is three 1-0 defeats in a row.
Thauvin scored the only goal when he volleyed Dimitri Payet’s free-kick in from close range. Di Maria and Benedetto both had goals disallowed for offside.