That law applies to concealed blades. If it is visible you are actually allowed to walk down the street or into a public park with a sword... Probably aren't allowed to have it unsheathed in your hands swinging it around though, they probably get your for disrupting the peace or something like that. At least that's how it is in California :3
I wonder how many hours of anime that guys watches a day 
Da fuck, you can only "transport" blades (from a place to another place, in cars or big boxes) in France, whether concealed or not.
If a blade is apparent on you, or concealed but easily identifiable, you're sure people will notify police.
If for whatever reasons you're searched and they find a pocket knife, you can be charged
or at least confiscated, except if they are nice.
Homeless dudes being searched and having their "to eat" knives confiscated is common in places where the police "number game" is big.
