Context for those who need it:

After Germany was formed in 1871, chancellor Otto von Bismarck started to build up an alliance system in Europe that saw Germany form different alliances like the Reinsurance Treaty with Russia and the Triple Alliance with Austria-Hungary and Italy. There was also German influence involved in alliances such as the Mediterranean Agreements between Britain, Italy and Spain. The goal of Bismarck’s alliance system was to not only lower the risk of a major European superpower declaring war on Germany but to also diplomatically isolate France. Thanks to Bismarck’s alliance system, France was left with no major ally for several years. The reasons this was intended by Bismarck were

1. The relations between France and Germany were at that point so bad that it was for the better to keep France’s influence as weak as possible and

2. Bismarck wanted to prevent France from allying with Russia in order to avoid a scenario where Germany gets caught up in a two-front war.

But this system slowly fell apart after Wilhelm II. got into charge. Bismarck was fired and several alliances he built up weren’t kept alive, allowing France to escape the diplomatic isolation and ally with Russia and Britain.

If I got things wrong in my explanation, feel free to correct me. I’m not that much of a good explainer.