Mario is too cunning, too cunning.
Making a public appearance to show that he is completely safe is something Yarebin had anticipated, but the timing Mario chose to appear was too perfect, perfect enough to make people back off.
The French police are really lousy, even the headquarters building has been visited by Satan, so if you want to take out Mario in France, you don't really need to worry about the police. This means the outer security at the Normandy landing commemoration doesn't need to be taken seriously; you can come and go as you please, even coming in and out eight times would not be an issue.
However, just because the French police are terrible doesn't mean the French military is terrible too, although there's room for discussion on that. After all, the current French military relies on the Foreign Legion for face, but the Foreign Legion is still a military force fully controlled by France, even though it's composed of foreigners.
