The Headquarters Allied Reconstruction Forces (HARF) was set up in the aftermath of the Dominion War to help manage the post-war situation. One of their tasks was to help rebuild Cardassia. (DS9 novel: The Never-Ending Sacrifice; ST - The Fall novel: The Crimson Shadow)
HARF's main building was in Coranum in Cardassia Prime's capital city; three years after its removal from Cardassia in 2385, the headquarters had been most deconstructed, but core buildings served as the embassy of the Federation. (DS9 novel: Enigma Tales)