A320 Captain reported encountering wake turbulence in cruise flight at FL320 when a B747 overflew them at FL330.

Narrative

While in cruise in smooth air at FL320 with the seatbelt sign off; we suddenly encountered moderate turbulence that lasted approximately 2 seconds. The autopilot remained engaged and while sudden and abrupt; we did not gain or lose any appreciable altitude and our speed remained within +/- 5 knots of our intended speed. We quickly illuminated the seatbelt sign and made sure the aircraft was still under control. By the time we did this; the air was smooth again. We called the cabin via the interphone to make sure everybody was okay. The flight attendants informed us that they were okay; although they had been quite startled; and that they would check the cabin for any injuries now that it was safe to do so. While they did that; we queried ATC as to whether there was an aircraft's wake that we could have flown through; as we suspected it to be wake turbulence based on the duration and nature. They informed us that it was likely from a heavy 747 that had passed 1000' above our altitude. The flight attendants advised us that there were no injuries in the cabin and that everyone was okay. I made a PA to the passengers informing them of what had happened and assuring them that everything was under control and we would not be experiencing any more turbulence like that. We notified dispatch via ACARS. We continued to ZZZ and landed without incident.