Brightly pronounced 'OP-lah', this exclamation is used much more in the north than here in the Touraine. Here you might occasionally notice doting parents swinging a small child over a puddle using it in the sense of 'over we go' or 'wheee'.
In Lille though, you could hear Hoopla ! several times a day. It is especially noticeable that when waiters deliver your meal they put the plate down with an Hoopla ! Apparently, producing the dish just as we ordered it is something of a magic trick in Lille. We found this rather disconcerting at first, fully expecting the next thing to be drum rolls and coins appearing from behind our ears.