I was in the cavalry,In Mali (for exemple) before the ground forces begun to fight,the special forces were fighting the terrorists with their helicopters (the special forces have their own helicopter fleet),then the cavalry equipped with light armored vehicle,and VABs,VBCIs,light 'tanks' (AMX10RC),with a big support of the air force and artillery,then fought and took the place of the special forces.
We saw that small forces,very mobile,with an excellent support can annihilate the enemy,with small casualties (9 french soldiers (8 in reality,one died in accident) against +1000 terrorists,so a ratio of 1 french soldier killed for +100 terrorists (1:+100) ) 300 were captured,many vehicles destroyed etc... and the rest have fled.
Though,the intervention came as a surprise to the terrorists,they didn't know that the French could fight against them,so they didn't have the time to prepare themselves.... While in Yemen,they probably have seen the deployment of Saudi soldiers at the borders,and prepare themselves (defense etc..) in case of ground operation.
Deploying tanks in Yemen,would be a wrong idea i guess.
(sorry for my bad english)