If it's a glass panel sunroof I dont think it has drain tubes.
This type of roof has a wide seal rubber/ plastic and this seal can fail. I think a renault dealer can offer a replacement but it would be expensive. You may be able to reseal( metal roof to rubber seal) with a mastic. Also if its a glass roof open up roof and clean rubber seal then wipe seal with silicoln.
If it's a metal or cassette panel roof then the drain tubes can be found in the gutter area (eac corner) when the roof is open.
Maurice
March 2010