Probably true. It's a line frequently repeated by past French politicians (after Louise XV) who spent all their lives climbing to the top, only to realize how limited real power is even when one is theoretically the supreme commander (just because all subordinates have their own brains, indulging in all sorts of corruptions while pretending to obey bureaucratic orders). The implication of that helpless exclaimation is that "I can't care less after I die." Louise XV lived a very debauched and short life. DeGaulle probably only repeated that statement when he was old enough to escape the consequences of his policies. Louise XVI was too young (because his predecessor Louise XV died early) and was still alive when the mob came for his head.
The retirement plan for the supreme king is death.