The Multicolor Tiles are the first two Queenies (single expanion modules) for Copenhagen. They are separately labeled, but they are packaged together, and will only be sold as a pair.
To get a multi-color tile, you have to discard cards in the exact color combination of the tile. You can get a one card discount if, when placing the tile, one of the squares is touching a previously placed tile of the same color (as normal), but you can only get this discount once, and only of the color it is touching (if it is touching more than one color, you can decide where to get the discount).
The size three tiles are added to the game in addition to the normal tiles, whereas the size 5 tiles replace the normal size 5 tiles, keeping the competition for them high. The size 5 tiles also feature completely different shapes for an new challenge.