Red Star’s Marko Gobeljic halved the deficit early in the second half, but further strikes from Marquinhos and Kylian Mbappe made the three points safe.
The result ensures PSG progress to the last 16 as winners of Group C, two points ahead of second-placed Liverpool.
The Reds snatched second spot by beating Napoli 1-0 at Anfield, meaning they progress ahead of the Italian side on goals scored.
PSG started their European campaign this season with a last-gasp 3-2 loss on Merseyside and Tuchel is delighted with the way his team have developed since then.
"The same players played against Liverpool [on matchday five]. It's not about the system, but about the attitude. It's really hard to win here and the guys played magnificently," he told RMC Sport.
"I really liked our reaction after the goal. We controlled the game. We played with a lot of risks and we sometimes forgot to close the spaces.
"Now, we're in the last 16. Congratulations to all the players and staff. It was a difficult group with a lot of quality. It was hard, especially after our first match in Liverpool. The team showed they could play together."
PSG president Nasser Al-Khelaifi hopes to see the team take their renewed confidence into the next round, the draw for which takes place next Monday.
"We're very happy to have achieved our goal: to be top, and not playing against a big team in the last 16," he said.
"It's not easy to play here. I'm very proud of my players, the coach, the staff. We've shown we're a great team. We were full of confidence."
PSG return to Ligue 1 action this weekend looking to continue their dominant domestic form.
Tuchel’s side have won 14 and drawn two of their 16 league matches so far to lead the table by 13 points going into this Saturday’s trip to Dijon.