The building being renovated is the marine biology lab of a Paris university. You used to be able to pay to go into the ground floor aquarium, where they had tanks with sea horses, jelly fish etc. It was fairly basic, dark and damp. Now there is a brand new 'Biodiversarium' at the far end of the boardwalk. The upper floors of the old building are still working laboratories, so I assume the ground floor will be refurbished for scientific use.