This thread demonstrates what a boringly reliable car the Jazz is. I have yet to hear of anyone laying in a wet gutter fixing the oily bits of their jazz. Even the fuel gauge and reserve tank seems to be reliable, right up to the point where the car stops when the tank is empty.
We're almost back on topic. Which is how far the Jazz can carry on running when it says that the fuel tank is empty?
That's a how long is a piece of string question. It depends on speed driven, car load, ambient temperature, engine and transmission temperature, tyre pressures, any stop/starts, traffic density, type of road, any gradients, altitude above sea level, and a few more variables I can't think of at the moment. All you can be absolutly sure of is the car will stop when the fuel runs out.