A tubular reactor for thermally cracking fluorohydrocarbons has a burner system (1) with feed lines (3, 4, 6, 7) for a mixture of fluorohydrocarbon and fuel gas and for flushing gas and oxygen or air provided at one end of the tubular reactor. This burner system delimits the end face of a combustion chamber (2) which, near the burner system, is provided with an ignition branch (9) and devices (10, 11, 12, 13, and 14) for feeding and distributing a liquid. The combustion chamber is adjoined by an absorber of cylindrical blocks (21) with bores (22) parallel to the reactor axis for a liquid product stream and a gas discharged from the combustion chamber. The bores lead into a downstream annular chamber (28) which is provided with a branch (29) for discharging gas and liquid. The other end of the reactor has a pressure relief orifice (33) which is connected via a duct (32) to the combustion chamber (2).