Tartuffe is about rich people with rich people's problems. Sure, the action all takes place in one room, but it's a darn nice room in what we have to assume is a darn nice house. Molière doesn't really tell us much about the place, but think about it: nothing would be happening if Tartuffe didn't stand to gain a lot of cash by duping Orgon and family. As you might expect, Orgon made his money, at least some of it, by serving the King – it's never really clear – but it's safe to say he probably had some kind of lucrative enterprise going on back in the day. As it stands, he's getting older now, he's looking to pass his money on to an heir or two. There's no better place to stage a comedy about inheritance than in daddy's mansion.
Now, in terms of the big picture, all this takes place at a time when Louis the XIV, the Sun King, reigned. He was a big deal – he was the Sun King after all – and to serve under him or to have anything to do with him was a, well, big honor.
At the same time, it's important to remember that the Catholic Church was an equally big player. To claim allegiance to God, as Tartuffe does, was to associate yourself with one heck of a powerful institution. France itself had been rocked by decades of religious conflicts between the Roman Catholic majority and the Huguenot Protestant minority. By the time Tartuffe was written, the worst fighting was over; the Huguenots were tolerated, but the Catholics reigned supreme. In any case, Tartuffe's less than holy behavior led to some controversy in and outside of the play – but you can read more about that in the "In a Nutshell" section. Let's just say Molière's playing with fire here.