Megane doesn’t start, please for help

Hello together, who can help me ? my Megane 1,6 16V, Bj 2003 only jumps on when he likes. The car was therefore several times in different workshops, unfortunately never found anything. The moto is then not orilt then, it only burns all lights. After long attempts he comes then eventually. But unfortunately not always. Does anyone in this world have the same problem or someone knows what that could be. I am grateful for every hint.