It's really a family affair ; the director is Xavier Gélin (sadly ,to die at 53) , the stars are his father ,Daniel Gelin,whose career was brilliant and his half-brother ,Manuel Gélin.
A scientist has invented a youth serum:overnight ,the seventy-year-old turns into a toddler ;the beginning of the movie is quite promising ,if awkwardly directed : a hippie sees the little boy driving his car and swears he won't touch grass anymore ; then the toddler meets his son ,a renowned chef and it's much fun to hear this thirty-something man call a four-year-old "papa ".
Unfortunately , things deteriorate beyond that point :the gags become repetitive ;the appearance of the thirty-year- old "version" of the professor (played by his own son Manuel) is a panting attempt to rekindle interest in a worn-out screenplay.Only the last picture is ,relatively speaking , surprising.