Excerpt from the back cover of C.I.T.Y. 2000, mentioning a sequel. Source: MobyGames user game nostalgia.
C.I.T.Y. 2000, also known as City in Trouble Year 2000 is a point and click adventure game with puzzles, developed by Rollogame Ltd. and released in 1993 by Aditus, Inc. You play as Jon Daring, an American secret agent on a mission to stop the evil drug lord S. Rooter to take control over London. The game uses a classic inventory system and live-action cutscenes.
C.I.T.Y. 2000 itself is not very rare by definition, since few copies can be bought on eBay and Amazon; the game also has been ripped and its digital copy is available online. However, the back cover of the box (at least in the Canadian edition) mentions C.I.T.Y. 2000 Paris, and indicates it's coming soon. The website LegendsWorld indicates it is "very rare", but it is so far the only piece of information suggesting its existence.
Very little can be found about the two companies: Rollogame has been involved in the making of at least 3 games (C.I.T.Y. 2000 for PC, Castelian for NES and Dream TV for SNES) and Aditus was a Montreal-based publisher. With no actual evidence of its release, and no copy available in any form, C.I.T.Y. 2000 Paris's existence remains unconfirmed.