Call the fire brigade (101).
Do not try to get into the basement, it’s very dangerous.
If you live on the ground floor and smoke appears in your apartment, open windows (but not the entrance door) and then leave your apartment, having informed your neighbors on the danger. Wait for the firemen in the street. It is recommended to open windows on the top floors too.
If of you have got into the basement on fire, bend down or lie down on the floor and make your way to the exit. Try to breathe through a fabric or a cloth. If you have lost the way, try to define in what direction the smoke extends more, it means that the doorway is most likely there.
Note: When fire breaks out in the basement, there is a very high temperature because of weak air flow. Thus it’s possible to be guided after it or by touch along the walls. Nevertheless, if the exit is not found, do not despair, lie down in a pass where the temperature is relatively low, and try to cover yourself with something. Sooner or later you will be found out by rescuers.