The Ligue 1 champions were beaten 3-1 at Camp Nou as Barca sealed top spot in Group F at the expense of their opponents, who qualified for the last 16 as runners-up.
On Thursday, Catalan police announced that some PSG supporters had been attacked close to the stadium and had been admitted to hospital.
A statement released by the police confirmed that the first incident occurred at around 23:00 local time on Carrer de Felipe de Paz, close to Camp Nou.
According to the release, "a French citizen" was stabbed "by two individuals dressed in dark and with a balaclava".
A short time later, a group of three supporters were attacked, one of whom had to be transported to hospital after being stabbed.
"The police are working to clarify the exact circumstances of the incident and arrest those responsible," the statement concluded.
The incidents come hot on the heels of Spanish authorities looking to clamp down on football-related violence after a Deportivo La Coruna fan was killed ahead of their fixture at Atletico Madrid last month.
