The showpiece match between Liverpool and Real Madrid at the Stade de France in May was overshadowed by serious problems surrounding the stadium.
Dangerous crushes formed as a result of access issues and many fans were tear-gassed or pepper-sprayed by police.
Some of Klopp’s relatives experienced the trouble first-hand, but they did not tell the German until afterwards.
“I met only a few (people) who were lucky,” Klopp told the club’s website.
“All the rest I met – my family included – had massive struggles outside. I think it is clear it was massively mis-organised. Whoever was responsible was not prepared for that.
“My family sent me messages before the game, ‘We are in the stadium, good luck’ and all these kinds of things – but they were not. These kind of necessary lies you receive.
“Then after the game we had this little party. My missus was not ready to party, still exhausted from all the things around.
“I think all the things that happened there made it possible that the smallest problem we had that night is that we lost the final – incredible after a Champions League final.
“It was obviously really difficult. I was not outside but so many people told me the true story and they were all the same story pretty much, so I know what happened.”
The 1-0 defeat in Paris meant a season in which the Reds threatened to win a quadruple ended on a sour note after they missed out on the Premier League title by just a point the previous week.
Klopp, however, insists the disappointment is now behind them.
He said: “I was happy when the season was over – not exactly the way it finished, but still happy that we could go on holiday.
“We had the holiday long enough. I’m more than recharged. Absolutely fine, happy to be back, everything is good.”
Another positive from the summer has been the decision of Mohamed Salah to commit to a new three-year contract and end considerable speculation over his future.
The prolific Egypt forward, who has scored 156 goals in 254 appearances for the Anfield club, had been entering the final year of his previous deal.
Klopp said: “I knew it would happen, it was always clear Mo wants to stay, but it’s an important contract, different things have to be considered and that’s what takes time sometimes.
“He is very happy now that he can extend his time here. We are very happy, a world-class player.
“Imagine you have to sign Mo Salah now – he’s in another club and you want a player with the numbers he created over the years. It’s pretty much not possible. But we have him and he wants to stay – very good news.”
Liverpool, who head to Asia for their pre-season tour this weekend, begin their 2022-23 campaign when they face Manchester City in the Community Shield on July 30.