Hangar 13 just posted a message to PC players of Mafia III and updated it with patch status.
The update says the team has a PC patch running that supports 30, 60, and unlimited fps options with more improvements. They are currently verifying the patch and testing it. Read the full update statement below:
We currently have a patch running here at the studio that includes 30, 60, and unlimited frames-per-second options in the video menu, among other improvements for the PC version of Mafia III. We’re verifying the patch now to ensure everything is working as expected. If everything goes well, we expect the update to go live this weekend. We will be keeping the PC community up-to-date on the status of the patch throughout the weekend and thank you for all the feedback!
Mafia III is now available on PlayStation 4, Xbox One, and PC.