Where It All Goes Down
Czechoslovakia, 1948 to late 1970s
Kundera refers to Czechoslovakia under the Communist regime as the "Republic of Forgetting" (VI.2), which makes the country an ideological setting as much as a geographical one. Because Kundera focuses on the systematic revision of history by the Communist Party, Prague, as the capital city of both the country and the region of Bohemia, is the ideal setting for much of the novel. Of course, Prague is also the biographical backdrop of Kundera's own political and professional drama.
Now, Prague did remain relatively untouched by the ravages of World War II, and this means that the city actually has a well-preserved history in the art and architecture that has survived through many centuries. The preservation of Prague's story in its monuments and buildings is a nifty juxtaposition with the Communist agenda of erasure.
Prague becomes a kind of Garden of Eden for dissidents like Kundera and Tamina: they've been expelled, and they can't go back. Neither of them particularly yearns to return, but they do look back to their lives in Czechoslovakia with a tinge of bitterness.
Kundera also uses the language of falling to describe his ousting from the Communist Party. It's no mistake that his fall echoes a more infamous fall of another bright star from a great height. (Yep, we're totally talking about Lucifer's fall from heaven.)
Prague might not really be as pristine as the Garden of Eden, especially in this era, but it's an integral part of the characters' identities. So much more is the shame, then, when Clementis is erased from that picture taken at Prague Castle. Communist Czechoslovakia may be the "Republic of Forgetting," but Prague is the city that endures.
Side note: Czechoslovakia no longer exists. After the Velvet Revolution, the country dissolved into its constituent parts: the Czech Republic and Slovakia. Although Kundera wrote the novel while Czechoslovakia existed, this dissolution adds another dimension of fictionality for modern readers.