A file image of cannabis resin. Photo: AFP
The mother of the infant took him to the Longjumeau hospital in southern Paris after she noticed the child seemed ill.
When the baby's father arrived at the hospital soon after, he suggested that his son may have swallowed a small amount of hash resin that had been lying around the house.
Tests revealed that the baby had indeed ingested cannabis, and the child was kept overnight at the hospital for monitoring, reported newspaper Le Parisien.
Meanwhile, the 25-year-old father lost his temper, lashing out at staff members of the hospital and at his wife for not paying enough attention at home.
The man was arrested at the scene, and will appear in court on Tuesday.
Another case of unintentional cannabis ingestion hit the headlines in France earlier this month when a butcher was slapped with a jail term after he gave his colleagues a cannabis-laced chocolate cake.
It was meant to be a prank, but the victims did not see the funny side.