The fullback is in his second season at Barca after last summer's arrival from PSG.
He told France Football: "It was at the end of Euro 2016. One morning, he (Digne's agent) took his phone and said, 'Barca is on you, they are very interested, we'll have to decide quickly'.
"I did not even have to think, it was all seen. Let's go. It was Barca and nothing else. We are still talking about the biggest club in the world and my childhood dream. I could not refuse.
"When Barça wants you, the leaders make the effort and put the price. The question of money had not even arisen."