PSG swept Inter aside 5-0 in Munich to win a first ever Champions League title.
Reflecting on the victory, Dembele recalled to France Football: "Before the game, on the bus, Gianluigi Donnarumma gave letters to all the players, to all the staff. He wrote a little message of encouragement, saying that what we have done this season has been exceptional. And it was something strong.
"And he wrote it in French, in English, in Portuguese, for everyone. It really motivated the whole group. We already had the motivation, but after this gesture we had even more. It was a very nice gesture from him."
Dembele also revealed, "This team spirit, it is thanks to this that we have become much stronger. We think about the collective first, before ourselves. And it is also thanks to this that Paris Saint-Germain became champion of Europe. Everyone defended, everyone attacked."
Luis Enrique demanded I change
Dembele also commented on how coach Luis Enrique has changed his game.
He said, "When you look at Achraf Hakimi: he scored in the quarter-finals, in the semi-finals, in the Champions League final, despite being a defender. He defends, he attacks, he makes a lot of effort.
"And that is what I do too, and with the coach we spoke about it at the start of the season.
"He told me that I have to take charge of the team, that I have to set an example for the younger players, that I am the first defender of the team. And the message got through."