This is the Lausanne treaty (which Turkey is a signatory of, and which stipulates that Greece shouldn't build naval bases on islands, which it hasn't).

There's also a treaty between Greece and Italy, which stipulates that there will be no army on some islands, the violation of which Italy apparently has no problem with. I don't understand by what right an unrelated third party complains about it, it seems to me about as relevant as Greece complaining about a treaty between Colombia and Brazil.