To be short: the front line just ended and both sides respected Swiss neutrality.

The point where the Western Front met the Switzerland is sometimes called "Kilometre Zero"^(1) and it really was the southern end of the Western Front. As you can see from this map, the French line stopped at the Swiss border, whereas the German line continued around Swiss territory for a little less than 1 km. Generally speaking the warring parties respected the neutral border, which was clearly identifiable thanks to bunkers and observation posts flying the Swiss flags, but there were occasional shots fired into Switzerland by mistake.^(2)

The area near kilometre zero was also where, on 2 August 1914, the war claimed its first dead: the French caporal Jules André Peugeot and the German Leutnant Albert Mayer.

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1. Samuel Goldschmidt, "1914 : Pfetterhouse, le Kilomètre Zéro", from RTL, online, https://www.rtl.fr/actu/debats-societe/1914-pfetterhouse-le-kilometre-zero-779399487
2. Andrew Whitmarsh, '"Kilometre Zero": Where the Western Front met the Swiss frontier', on Switzerland and the First World War, online, http://www.switzerland1914-1918.net/blog/kilometre-zero-where-the-western-front-met-the-swiss-frontier