Madaline wants to put carpet over tile over parquet flooring. The following answer also applies to vinyl over ceramic tiles.
Well, aside from the floor getting so thick that doors may not open and counters will appear to be sinking into the floor, there are a couple important things to know about carpet or vinly over tiles.
The grout line between the tiles is always a bit lower than the tile surface. This grid pattern will eventually show through the carpet. We call that 'telescoping', and it is even more pronounced if you try to put vinyl flooring over tiles. If you use a thick underpad, telescoping will be minimized, but not eliminated. If you put a hard surface, like plywood or even maisonite, over the tile first, you will not get the telescoping at all. You may want to glue the wood panel down to prevent edges from shifting up.
One other detail: the nailing rack that typically holds a carpet in place has to be nailed through the grout, not through the tile, so you should pull out all the regular nails intended to attach the rack to the floor, and nail them back through the rack where they will line up with the grout pattern.