Protesters clashed with riot police at Montreal's Palais des congrès for a second day as a job symposium for Quebec's northern plan was held inside under guard.
Dozens of members of the Réseau de résistance du Québecois joined aboriginal groups and students for the planned protest.
They faced off with riot squads in full armour stationed around the downtown conference centre.
Police arrested 90 people after declaring the protest illegal midday.
Officers blocked the convention centre's entrance, as hundreds of job seekers waited outside.
Inside the building, about 100 businesses set up kiosks under police watch, for the second day in a row.
A protest outside the convention centre Friday erupted into violence with police using tear gas and sound grenades on rock-throwing protesters. Seventeen people were arrested.
Plan Nord targets natural resources
Companies hope to recruit workers for the Plan Nord, Quebec's ambitious, $80-billion economic development plan.
Some First Nations are concerned about how the 25-year strategy is unfolding.
"I'm willing to share these resources in Nunavik, but nowhere with my Eskimo ears did I hear anything about Quebec willing to share the resources they claim is theirs," said Harry Tulugak, who lives in Puvirnituq, an Inuit village.
Several aboriginal groups have set up tents outside the convention centre.
A group of Innu women are expected to join the protest, after travelling by foot from their home community of Uashat-Maliotenam, on Quebec's Lower North Shore.
The 900-kilometre journey took a month.