origins of sabotage

My friend and I are having a dispute on the origins of the word sabotage. I thought that the word derives from Belgian railwaymen’s practice of unseating rails from their shoes (sabots) during the great strike of 1905. However, she contends its origins lie in France, and that it was coined when striking factory workers inserted their shoes (sabots) in machinery renderring it inoperable. Could you clear this up for us?