Profile - Planning for "The Day": France, 1871-1914

This is the follow up that we promised to our earlier look at German planning, in which we will review French planning for a war with Germany, from the end of the Franco-Prussian War to the outbreak of the Great War. 

In the aftermath of the disaster of 1870-1871, the French began to totally revamp their military system.  This took a while, and was done not without acrimony, as rightists and leftists had radically different ideas about what the army should be like.  Conservatives favored a smaller force of well-trained long term professionals, despite just such an army having gone down to defeat at the hands of Germany’s mass armies, while the Liberals and Radicals favored a mass patriotic national militia, which also hadn’t done very well in the recent war.  In the end, France rejected both the long-service professional force and the mass national militia, in favor of a conscript-based mass army, built around a large professional cadre, more or less emulating the Prussian-German model.  Naturally, for many years their planning was defensive, and focused on the threat of a German offensive from Lorraine, as we’ve noted during our earlier discussion of German planning. 

Unlike the German plans, which actually were executable operational schemes, French war plans were essentially contingency deployment plans.  That is, the were intended to position French forces in optimal ways to cope with possible German offensives; German moves would determine French responses. 

French planning was helped by some knowledge of German planning.  All armies closely monitored the military literature of the other armies.  In addition, military attachés serving on embassy staffs in other countries and occasional official observers invited to attend various country’s annual maneuvers, often could pick up valuable information.  The French could also read a map, and the increasing density of German rail lines converging on the Belgian-Luxembourg frontier suggested large numbers of troops were destined to deploy there.  And, of course, there were spies; at times it’s still impossible to determine how some information came into French (or anyone else’s) hands. 

The Belgian Threat.  Although they tended to dismiss the possibility of a German move through Belgium to outflank their frontier defenses, the French were aware of the possibility, and in 1894 their Plan XII provided covering forces to impede such an attack, to buy time for the intervention of stronger forces.  Some time after 1900 they also became aware that the Germans might use reserve forces in a front line role, and although believing reservists of limited value, in the 1903 Plan XV they began to make some use of reserve formations.  The following year a German officer, possibly a general on the General Staff, sold the French a copy of the German plan of concentration, which clearly indicated a major move into Belgium.   In December 1906, after much discussion, and probably prompted in part by insider information on German wargaming earlier in the year, the French introduced Plan XV bis.  This assumed that rather than launch an immediate frontal attack from Lorraine the Germans would open hostilities by coming through Belgium, and so the French placed strong forces northwest of Verdun.  Plan XVI of 1909 placed greater emphasis on the risk of a German attack through Belgium, though still not considering that it might be the main thrust.  In 1911 Chief of the General Staff Victor-Constant Michel (1850-1937), believing that the Germans would undertake a massive movement through Belgium, proposed a new plan.  The French should hold in Alsace-Lorraine, and undertake a massive counteroffensive into the German flank in Belgium, an operation that would require extensive integration of the reserves into the active army.  The resulting uproar led to Michel’s resignation and replacement by General Joseph Joffre (1852-1931). 

Joffre takes Command.  When Joffre assumed command he made some modifications to Plan XVI, but also began to think on a grander scale, seeking to return the French Army to the offensive in the event of a war.  He initially proposed a preemptive offensive into Belgium, to head off the Germans, which found absolutely no political support, since it meant that the British would never come to France’s aid.  So Joffre kept working.  The end product was Plan XVII, approved in the Spring of 1914.

Prior to Plan XVII all French war plans had been defensive, intended to blunt and then beat back a German invasion.  But for several years some French soldiers had been trying to return to an offensive doctrine.  Among them was Ferdinand Foch (1851-1929), an artilleryman.  In several books and lectures, Foch’s formula for a successful offensive doctrine involved a combination of the firepower of the later famous “French 75” and rifle fire from well trained, highly motivated infantry culminating in close assault with the bayonet.  These ideas spread, but became warped.  Some of the more ardent younger officers in the army, such as Col. Louis Loyzeau de Grandmaison (1861-1915), preached the notion that well motivated infantry were sufficient to undertake the “offensive á outrance” (arguably, “offensive to the utmost”) with the bayonet more important than the bullet or the artillery round.  Grandmaison reached the peak of his influence just about the time Joffre became chief-of-staff.  While officers like Foch, in 1914 commanding the XX corps d'armée, or Col. Philippe Pétain (1856-1951), commanding the 33e Régiment d'Infanterie, understood the relationship between firepower and spirit in the offensive, many others missed the first half of the equation.   

Plan XVII rejected a purely defensive strategy.  It was a contingency plan for an offensive-defensive strategy.  Rather than stand up to a German offensive, the French would counter it with one of their own.  To effect this, French forces were deployed in such a way as to be able to counter any of several possible German moves; once the German offensive got underway, the French would initiate a counter-offensive.

Based on French intelligence about German wargaming in 1905, Plan XVII presupposed that Germany would undertake a diversionary incursion into Belgium, while making her main effort in Lorraine, against the line Verdun-Nancy-St. Die.  So they put three armies on the German frontier, from the First Army on the right close to Switzerland to the Third Army close to Luxembourg.  The Fifth Army was posted mostly northwest of the Third, generally concentrated south and east of the frontier with Luxembourg-Belgian, to cope with the German thrust through those countries.  The Fourth Army was in reserve more or less equidistant behind the Third and Fifth; depending on what the Germans did, the Fourth Army was to move to support the troops in the threatened sector. 

Like the German plan, the Plan XVII had some notable flaws.  The most important was the “offensive á outrance.”  The plan assumed that the French would respond with a vigorous counter offensive after the Germans initiated operations, but the plan included the phrase “The intention of the commander-in-chief is to deliver, with all forces assembled, an attack against the German armies,” which suggested a pre-emptive offensive.  Then there was the Grandmaisonite notion that spirited frontal attacks with the bayonet were the way to win wars.  There was also the assumption that German reserve divisions were no more effective than French ones were believed to be.  By implication, if the Germans did beef up their armies with reserve divisions in the front lines, they would actually be weakening their forces, since these troops would not be able to stand up to vigorous French infantry attacks; in 1913 French general de division Édouard de Castelnau (1851-1944), deputy chief-of-staff of the army, actually remarked that if the Germans came through Belgium in force “We’ll cut them in half!”