Complex sentence: Because they depended directly on the Comintern, with Duclos as their intermediary, it was often they who were on the front line when the order to fight came from Moscow, while the various French groups were more attentive to the French national political climate.
Split into simpler sentences: Because they depended directly on the Comintern, with Duclos as their intermediary, it was often they who were on the front line when the order to fight came from Moscow. The various French groups were more attentive to the French national political climate.