Matuidi, 29, could not hide his disappointment after the match and felt France would have to wipe the result from the minds quickly.
"A lot of regrets, a lot of regret obviously," he told reporters. "When you lose in a final you can only have regrets.
"It is too soon to speak about how to recover yet. The main feeling is the disappointment. We need to forget about it first and then we will see what happens.
"Obviously we will need to act fast because there are the [World Cup] qualification matches in September. We will need to be ready then.
"It is very difficult because we have done the job in order to play the final and win it. It is always very tough to lose in a final. It is also what football is about. We will have to bounce back, go on holiday and then prepare for 2018."
Matuidi felt that while France were lacking in energy on Sunday, they still had enough possession and chances to beat Portugal and win the tournament.
Indeed, Les Bleus had 18 shots to the 10 from Fernando Santos' side, but they could not find a way past goalkeeper Rui Patricio and the Selecao's resolute back-line.
"It was very close - we got chances even if we were not very fresh, not physically at our very top," said Matuidi.
"Despite that, we had chances to score. We got the possession. They also got chances but I think less than us. Then we were also tired in a way and that is to be taken in account close to the end of the game.
"The Portuguese team has the merit to trust until the end that they can do it and they have been rewarded for that."
The crushing defeat, though, has not left Matuidi without a sense of perspective over the positive effect France's performances over the last month have had on the host nation.
He continued: "We can have regret but also be proud of what we achieved in the tournament. It was good, even very good.
"We were able to unite the French population and there was a lot of passion from them. We gave some happiness to people who love football and maybe some who were not a big fan of football previously are now starting to like it."