I agree with you, Spain is the favorite team to win against France because they have defeated stronger opponents in this tournament. Spain defeated Italy, Croatia, and Germany, they won against these strong teams, and I don't think France will be able to stop them in the next game, however, since the start of this tournament France has only scored three goals, one was a penalty against Poland. France, in my opinion, is a weak team in this tournament since they drew with Poland, a team that every opponent defeated in the group stage, they were just lucky to win the penalty shootout against Portugal. Spain on the other hand has scored 11 goals since the start of this tournament and has not draw any of their games, which is why I am very confident in their game, but if France wins, I believe they will be lucky with how Spain has performed.
The performance of Spain is quite surprising, they could beat strong teams in this competition. Although Spain isn't a part of the favorite teams to win Euro 2024, Spain becomes a team that has good teamwork in each match. That's why they always could beat strong teams, including Germany. In the next match, France will be the opponent. France is one of the favorite team to win this Euro 2024 but their performance looks not really convincing. I agree with you that France is just lucky to win against Portugal.
France is surely a strong team but they couldn't optimize their potential. If France could play with their best, France can easily beat other teams because France is one of the strongest teams in this competition. Since Mbappe got an injury, I see that France couldn't build their attack well. In my opinion, the players of France is trying to play more individually.