PARIS — French student unions vowed on Friday to keep up protests after scoring their first win in a campaign that is increasingly supported by Paris's elite universities, with 141 schools still shut around the country, according to the education ministry. The protests, now in their third week, have snowballed into a wider movement, with some university students weighing in to express their anger over what they call a dysfunctional system, worsened by spending cuts spurred by France's budget crunch. The unrest poses a challenge for the government, which must balance demands for more education spending with the need to rein in public debt, and risks rekindling the kind of street protests that have historically forced French leaders to retreat on austerity measures. Student and teacher unions have called for another round of nationwide school strikes next Tuesday. Police cleared a blockade at Assas university, France's top law school, in central Paris on Friday morning, BFM TV showed. Nearby, elite engineering school Mines Paris was also disrupted by blockades. The Institut Catholique, a