How to have access to the top floor of the buildings in Lumiose City ?

Question

I was surprised since I knew it was possible to get the TM Echoed Voice in the 5th floor of the Richissime Hotel, but I was only able to get to the 4th floor of the buildings
It is rather annoying as it is the case for lots of buildings, and I think interesting items are there.
So do you know how to get these top floors ?

Comments

Are there any specific buildings that you want to know about?

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Well as I said I really want to know about the Richissime Hotel, but there is also a building where there is an Expert Belt and I really want this item, so if you know about this building as well, it would be great

Answer 1

According to Bulbapedia, the fifth floor can only be reached once you're at the fourth work level (30 or more tasks completed perfectly), and you only have 40 seconds up there. The TM is given to you by a lady in a bathroom.

Comments

Thanks KRLW890