It is located on rue du Château d'Eau, in the 20th arrondissement. It is about 1m40 wide!
The ground floor is a small shop. Actually, the first floor communicates with one of the neighbouring flats. Legend has it that there was a passageway between two streets and between two buildings and that the heirs did not agree on its use so it was decided to fill it in with a very small building.

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