Griezmann announced his choice just before the World Cup.
"Difficult to reject Barça? Very difficult," he said.
"You have Barça who loves you, who calls you, who sends you messages, either through the players or with my family.
"And then there's the club where you feel at ease, you're an important player around which they build a project. They did everything possible to make me stay.
"What made the scales tilt? Seeing my teammates and especially the coach after a game in which they whistled at me; He (Diego Simeone) came to my home by surprise to calm me down, talk to me and show me that I had his confidence."