His teachers described him as lazy, he didn't submit work on time, so that his mother had to employ tutors to educate him at home. Lissajous, who was about two and a half years younger than Foucault, was one of his few childhood friends.
Kanyang mga guro ng inilarawan sa kanya bilang tamad, siya ay hindi magsumite ng trabaho sa oras, sa gayon ang kanyang ina had sa gumamit tutors upang turuan siya sa bahay. Lissajous, na noon ay tungkol sa dalawang kalahati at ng isang taong mas bata sa Foucault, ay isa sa kanyang pagkabata ilang mga kaibigan.