Your going to get a lot of replies along the lines of:
"FEAR THE LAW!!! THEY WILL COME FOR YOU!!! THEY HAVE LAWYERS!!! "
But in reality, unless you have a game with a lazyboy as the main character no one is going to care, or even know. If anyone was offended by their furniture designs being in your game, they would tell you, and you would remove them.
They will not care. Just like they don’t care about how its being sold unlicensed on turbosquid in the first place.
The only possible exception to this would be if you had a game where people use micro-transaction to buy furniture ( Like Play-station Home ). If that were the case, then they have a legitimate right to demand that you get a formal license with them, and there are a few cases that come to mind that went to court for similar circumstances.
But aside from that, no, you won’t have any problems. Worst case scenario is a cease and desist. But even that is extremely unlikely, especially for an indie PC game.
EDIT:
Quick note about the Iphone thing. If you had an Iphone in your game just sitting on a table as a prop, it is EXTREMELY unlikely that apple would come after you ( assuming you don’t have the apple logo on it ). But if the main character of your game had a PDA that was an Iphone ( Like the phone in GTA4 ). Thats a different story.
Rule of thumb is whether or not the object is “Front-and-Center”. If it is a core part of the game, and is present often, then you could possibly run into some issues. Its the difference between drivable cars in a racing game, and cars in the parking lot of a shooter. In a racing game cars are the star of the show, and if you want to use an official car you need permission. But in a shooter, with a car as an inanimate and unimportant prop, having a real car in it will not matter.
This of course all assumes you are not using any company logos or names. Even if the object is not “Front-and-Center” if you use a company logo your asking for it.