Ireland scored four tries to one in arguably their best home performance under coach Andy Farrell and with a potential meeting against host nation France in the World Cup quarter-finals, can claim a psychological advantage with the win.
"It was a hell of a game and it came down to (taking) chances. We did not take as many as we could have in the first half which made it difficult, but the lads hung in there," Sexton said at the post-match presentation.
"If everything goes to plan at the World Cup and we get through our group there is a chance we could play them again. So it is good to get that off our back in terms of beating them. They were the only team we hadn’t beaten."
Sexton believes the result is further evidence of the team’s growing stature under Farrell, having lost their previous three meetings with France.
"When new coaches come in and they bring a new way of playing it takes time," Sexton said. "The first time we played them during COVID we looked all over the place.
"Then when we went to the Stade de France it was a little bit better but still not ourselves. Today we gave a true account of ourselves."
Ireland number eight Caelan Doris (24) says it was one the toughest matches of his test career.
"It was a proper test match. It was one of the toughest first halves I have experienced. It was a battle the whole way through," he said.
"We knew it would be an 80-minute performance against these guys, they can make something out of nothing. We needed to be switched on the whole game and we were close to that. It was incredibly tough, with the threats they have. Physically it was very tough and mentally as well."
Ireland travel to Italy for their next fixture on February 25 and will now be favourites to lift the Six Nations trophy, and possibly the World Cup, though Doris said much hard work lies ahead.
"The momentum is with us so we are happy with the start, but we have three huge games to come and we have to keep working hard," he said.