The Austro-Hungarian and German empires invaded Serbia and Belgium which precipitated the invocation of defence alliances involving Britain, Russia and so on, thus started WWI, so pretty much, yes they did.
as far as I know Austria-Hungary declared war on Serbia and subsequently invading them (starting the war) then all other countries joined in.
even wiki says so. I might be wrong, but I can't remember being taught at school that Germany started WW1.
p.s. saying that I was in Germany in school so they might just made it sound nicer

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