The French developer has registered the domain name for SingularityPS4.com (spotted by Kotaku). In the past, the company has registered both HeavyRainPS3.com andBeyondPS3.com, so it seems pretty likely that the studio is already working on creating a game called Singularity for Sony's PlayStation 4.
The game's unlikely to retail with just the Singularity title though; thanks to the existence of the unsuccessful 2010 shooter, Activision holds all the rights to that name in multiple territories. As was the case with the Beyond domain though, just because a subtitle isn't present initially doesn't mean one won't be attached before the game is officially debuted.
Quantic Dream's current project, Beyond: Two Souls, stars actress Ellen Page and is expected to release sometime this year. Considering it's already been revealed that the script is 2,000 pages long though, it's probably not overly surprising that we haven't got a fixed date just yet.