By invading Switzerland, the French government had unwittingly opened up a new avenue for the Coalition forces to invade France. Along its borders with Belgium and Germany, France was well-protected by a belt of fortresses. But in the Jura Mountains on the Swiss frontier, there were only a few places like Fort de Joux and Salins-les-Bains guarding the region of Franche-Comté. Lazare Carnot regretfully noted that when Switzerland was neutral, France could ignore their common border. However, with Switzerland a belligerent, the French must deploy 40,000 soldiers to either occupy the country or watch the frontier.Duffy (1999), p. 155.
