▁French ▁front ier , ▁from ▁the ▁ ▁expected ▁to ▁be ▁mobil ised ▁in ▁the ▁ ▁( western ▁army ). ▁The ▁main ▁German ▁force ▁would ▁still ▁advance ▁through ▁Belg ium ▁and ▁attack ▁south wards ▁into ▁France , ▁the ▁French ▁arm ies ▁would ▁be ▁en velop ed ▁on ▁the ▁left ▁and ▁pressed ▁back ▁over ▁the ▁Me use , ▁A is ne , ▁Som me , ▁O ise , ▁Mar ne ▁and ▁Seine , ▁unable ▁to ▁withdraw ▁into ▁central ▁France . ▁The ▁French ▁would ▁be ▁anni h il ated , ▁or ▁the ▁man oe uv re ▁from ▁the ▁north ▁would ▁create ▁conditions ▁for ▁victory ▁in ▁the ▁centre ▁or ▁in ▁Lor raine . ▁ ▁Plan ▁XVII ▁ ▁Under ▁Plan ▁XVII , ▁the ▁French ▁pe ac etime ▁army ▁was ▁to ▁form ▁five ▁field ▁arm ies ▁of ▁ ▁with ▁" Groups ▁of ▁Reserve ▁Div isions " ▁attached ▁to ▁each ▁army ▁and ▁a ▁Group ▁of ▁Reserve ▁Div isions ▁on ▁each ▁of ▁the ▁extreme ▁fl anks . ▁The ▁arm ies ▁were ▁to ▁concent rate ▁opposite ▁the ▁German ▁front ier ▁around ▁É p inal , ▁Nancy ▁and ▁Verd un – Me zi ères , ▁with ▁an ▁army ▁in ▁reserve ▁around ▁Ste . ▁M éné h ould ▁and ▁Com mer cy . ▁Since ▁ 1 8 7 1 , ▁railway ▁building ▁had ▁given ▁the ▁French ▁General ▁Staff ▁six teen ▁lines ▁to ▁the ▁German ▁front ier , ▁against ▁the ▁th ir teen ▁available ▁to ▁the ▁German ▁army , ▁and ▁the ▁French ▁could ▁wait ▁until ▁German ▁intent ions ▁were ▁clear . ▁The ▁French ▁deployment ▁was