Nicolas Gaume, CEO, Mimesis Republic was mentioned in the 3dvia mp press release:
"3DVIA MP is an outstanding development engine that has given our team a collaborative work environment including low-level access for our programmers", said Nicolas Gaume, CEO of Mimesis Republic game studio. "The designers have been able to get results in record time while maintaining triple-A visual quality."
I think he is quite famous in france as he was president of known French game company called Kallisto etc. Anyways back to topic. On the FMX site it says:
Mimesis Republic designs, develops and operates a new generation of social networks: virtual 3D immersive worlds, by leveraging multiple types of gaming experiences to create new and increasingly synchronous social dynamics.
On the site of Mimesis Republic designs it says:
black mamba :
A universe and community in real-time 3D targeted at urbane cultures (Hip Hop).
Released in summer 2008 in partnership with: Universal Music, Sony Ericsson, Orange, Skyrock.
Looks like a GTA meets Singstar in Second Life 
But, as Helgason recently announced, there are also several Virtual Worlds and a MMO in works using Unity3D:
– 1 x full blown MMO being made with Unity
– 5 x virtual worlds being made with Unity
– 3 x well funded game portals being made with Unity
It's no surprise, with Networking (based on Raknet) included plus a GUI engine etc. The only think that makes me wonder a bit, is that Unity3D has no real external run-time binary format for loading scenes/objects/components data into Unity at runtime. People write their own serializers but I hope they will add their own format too. Currently the webplayer streams all levels into the memory, but I think there are plenty of use-cases where only a selective loading behavior is desired.
Btw. since the Second Life hype, there are so many companies working on virtual worlds … it soon will be crowded. I think there's a bigger one beeing produced in Berlin, too.