pascal lienhard knows this well. calling the moment a gate won't close properly, asking when it will be fixed. people worry. reporter: people feel safer with a gate? pascal: it's about the feeling of security. you need to understand there's no such thing as total safety. reporter: an exhibition at this library in marseille shows how more and more parts of the city have walled themselves in. areas marked red are off-limits to non-residents. elisabeth: many marseille streets were built in the 19th and 20th century by the upper-middle class, who carved up this area. these were private streets. and the city did not want to integrate them into the public network and also pay for their maintenance. this means many residents today have the legal right to close off streets. reporter: this city's hands are tied. though it does have power over new construction projects. mathilde: in the future, we'll withhold permits for housing projects that are designed as gated communities. reporter: it's the afternoon. school's done for the

pascal lienhard knows this well. calling the moment a gate won't close properly, asking when it will be fixed. people worry. reporter: people feel safer with a gate? pascal: it's about the feeling of security. you need to understand there's no such thing as total safety. reporter: an exhibition at this library in marseille shows how more and more parts of the city have walled themselves in. areas marked red are off-limits to non-residents. elisabeth: many marseille streets were built in the 19th and 20th century by the upper-middle class, who carved up this area. these were private streets. and the city did not want to integrate them into the public network and also pay for their maintenance. this means many residents today have the legal right to close off streets. reporter: this city's hands are tied. though it does have power over new construction projects. mathilde: in the future, we'll withhold permits for housing projects that are designed as gated communities. reporter: it's the afternoon. school's done for the