Sorry, I have no knowledge of common leak sites on Jazz. Just general tips
First check its only rainwater, not coolant ,perhaps from the heater hoses etc. . any chemical smell? Check the coolant level is not dropping. Slight possibility is windscreen washer fluid but this smells different.
Check the drain holes at the bottom of the passenger door are not blocked with dirt, dead leaves etc. These are just small holes or slots you can poke a wire or something through to clear. Some rainwater gets in via the window seals anyway. If this cant drain it tends too pool inside the door panel and can leak into the car. . Check the other doors while you are at it.
Also check as best you can in the scuttle area. This is the area below the windscreen where the wipers park etc. It may be covered behind a grill. There are usually drain holes , or even quite large drainage channels which allow rain water to drain away. These are easily blocked by dead leaves, dead bugs etc. which again can allow excess water to seek another way out , possibly leaking through small holes, gaps etc into the car. Clearing any blockages might solve the problem and the car interior will dry out.
But if the leak persists it may involve some detective work on your hands an knees, with a torch, mirrors etc. Water can travel quite some distance along seems, in depressions under carpets etc from the point where its actually getting into the car to where its finally evident as wet carpets etc.
Try to check initially when the car has had time to dry out a bit. . Use dry fingers to detect any wetness that may not be obvious visually, perhaps even powder your fingers with talcum powder or similar safe substance to help differentiate between damp and merely cold. . Then give the front of the car, windscreen, side windows etc a good soaking with a hose or buckets of water and check again for leaks. If you then discover a new leak it may help you in tracing its progress back to its original entry point, such as a wiring grommet etc .
