Complex sentence: The RPF advance caused panic in France, a long term supporter of the Habyarimana regime, which immediately sent several hundred French troops to the country, along with arms and ammunition, to bolster the FAR forces.
Split into simpler sentences: The RPF advance caused panic in France, which had long supported the Habyarimana regime. Several hundred French troops were immediately dispatched to Rwanda, along with arms and ammunition, to bolster the FAR forces.