There are 3 canyons 1st, 2nd and 3rd, the first 2 are exciting to run ... the 3rd canyon sort of peters out
Both the 1st and 2nd canyon can be scouted from the shore but boat scouting from an eddy should suffice.
The island/remains of dam at the top of the 1st canyon usually traps a tree or several trees on the river left channel, but there is a huge eddy upstream of the dam on River right ..There is a portage trail on River right allowing you to run laps if so desired.
Just like Jon says... Class II/III. Not too difficult for an intermediate paddler.
Or you can up the class a notch for the aroma of the farmland run-off spilling into the river
I was thinking of doing the Petite Nation river soon and may come along. I found a map on quebec whitewater
http://quebecwhitewater.com/en/river-level/view/9
but can't find any descriptions of the rapids. Does anyone have a link they can share. Greatly appreciated. Thanks.