"Everyone knows the answer: it will be symmetrical and destructive for bilateral relations," Medvedev said in a posting on his Telegram channel, Reuters reported.
"Who have they punished? First of all, themselves."
On Monday, France said it would expel 35 Russian diplomats over Moscow's actions in Ukraine and Germany declared "significant number" of Russian diplomats as undesirable.
"If this continues, it will be fitting, as I wrote back on 26th February - to slam shut the door on Western embassies," Medvedev said. "It will be cheaper for everyone. And then we will end up just looking at each other in no other way than through gunsights."