The two men were detained on Thursday as part of an investigation into the alleged food poisoning case at the centre in Lambersart, a suburb near Lille, prosecutors said.
As reported by The Local on Tuesday, the facility was closed on November 22nd.
This occurred after two staff members suffered burns to the mouth from eating the tainted potatoes.
The two men held for questioning were employed to prepare food at the centre, which also accepts pregnant mothers.
The infants there are younger than three years old.
A problem with the meals served at the centre was noticed by an auxiliary child care worker and a trainee who detected a suspect odour of grapefruit in the mashed potatoes being served, according to media reports.
They tasted the potatoes and immediately felt a burning sensation in the throat.
According to reports from sources, including Le Parisien and Europe 1, drain clearing fluid was mixed in with the purée.
The meal was not served to other adults or any of the children.
The centre has subsequently filed a complaint with police.
The investigation continues.