Question 1

Where is passage mignon?

Accepted Answer

passage mignon is in Toshima, Tokyo, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of Durarara!! does passage mignon appear in?

Accepted Answer

passage mignon appears in EP1 of Durarara!!.

Question 3

Can I visit passage mignon?

Accepted Answer

Yes. passage mignon is a real place you can visit. Check what it looks like on Street View before you go.

Question 4

Where was Durarara!! filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and passage mignon is one of those real places (EP1).