By Caroline Pailliez and Clotaire Achi PARIS (Reuters) -Dozens of black-clad protesters clashed with police and broke shop windows on Tuesday in Paris on the margins of a march for wage hikes. Regional train traffic was cut by about half as several unions called a nationwide strike, seeking to capitalise on anger with decades-high inflation to expand a weeks-long industrial action at oil refineries to other sectors. “The question of wages is the French people’s number one priority,” the head of the hardline CGT trade union, Philippe Martinez, said ahead of the otherwise peaceful march. “It’s m…