A Lufthansa Airbus A340-300, registration D-AIFD performing flight LH-758 from Frankfurt/Main (Germany) to Chennai (India) with 162 people on board, was climbing through FL190 out of Frankfurt when the crew stopped the climb at FL190 reporting a forward cargo smoke indication and decided to divert to Munich (Germany). The crew further advised they had environmentally hazardeous liquids on board. The aircraft landed overweight but safely on Munich's runway 26R and vacated the runway at the end, emergency services subsequently checked the cargo holds, the crew requested the emergency services also to inspect the crew rest area, where smoke detectors had also activated. The aircraft remained on the ground in Munich for about 5 hours, then departed again and is estimated to reach Chennai with a delay of about 6 hours. An air conditioning recirculation fan is suspected to have caused the smoke indications.