"Vi bor på den samme boulevard."
Translation:We live on the same avenue.
By definition, the words are not exactly the same.
en boulevard is a very wide road with trees on each side.
en allé is a road with trees planted on both sides, often leading up to a manor house.
In reality, many roads that do not fit the above definitions have Boulevard or Allé in their names.
The sentence "Vi bor på den samme boulevard." would only be used if they live on the same very wide stretch of road.