The 30-year-old moved to Camp Nou from Valencia for 20million in the off-season, as Barca looked to replace club legend Carles Puyol in the heart of their defence.
Mathieu was called up to the France squad as a replacement for Laurent Koscielny ahead of recent friendlies against Spain and Serbia, and played the full 90 minutes in a 1-1 draw in Belgrade on Sunday.
That was just his third international appearance but, with France due to host the European Championship in two years' time, Mathieu believes his status as a Barcelona player will aid his cause.
"Obviously I am the same player who was at Valencia, but after five years there I could have some great games and it wouldn't have made any impact," he told Le Parisien.
"Instead, after I arrived at Barcelona I had the feeling that people were not looking at me in the same way.
"Now I want to play some great games for Barca so I am selected for the next squad.
"I knew the French team when things were more difficult, yet when I arrived at Clarefontaine this week I felt that something had changed.
"It was said during the World Cup that this group was more together and I've seen that with my own eyes over the past few days."