To add more to the French crowd. Just finished watching the Sabalenka/Svitolina match, won by Sabalenka. No issues at all from either player during the match, but Sabalenka was waiting for the handshake at the net and Svitolina went right to the chair umpire to shake hands and go to her bench. The French crowd starts booing, and yes naturally you would do this.
However, in case they've all been living under a rock for the past year and half, Ukraine (Svitolina's home country) has been invaded by Russia and Belarus (Sabalenka's home country) has supported Russia. So yeah, she isn't shaking hands with Russian and Belarussian players. She's done it all tournament and most Ukrainian players have done this since the invasion.
Only hope is they are just booing the situation going on in Ukraine, but then they switch to cheering for Sabalenka immediately after. So typical French crowd again. Read the room, or in this instance court, people.