PSG were off to a flyer when defender Marquinhos gave them the lead 13 minutes into the game.
Argentina forward Angel Di Maria doubled the French champions’ advantage three minutes before halftime.
Leipzig’s defense were beaten once again as Juan Bernat profited from a defensive error to add PSG’s third eleven minutes into the second period.
In an interview with BT Sport after the game, Nagelsmann admitted that Thomas Tuchel’s men deserved to be in the final and pointed out his team’s errors that proved to be costly.
"At the end the ticket for the final for PSG is well deserved. First 10-12 minutes we played well. PSG has so much quality and at the end they were the better team, but football is sometimes like that,” the 33-year-old German said.
"We have to decide before the game if we want to attack early. In the first 10 mins we had three or four good moments and made two of three big mistakes.”
“When we conceded the second goal the belief of our players drained. At the end it was a question of character and we did it well in the second half.”
"It is not that easy to think of the good season but after a week it will be OK. We are a young team and will try to do it well in the next season. The players can come back and we can try for the Bundesliga and the cup."