The 14-year-old student who knifed a teaching assistant to death during a bag search at a school in France had just been reprimanded for kissing his girlfriend and specifically sought out a female supervisor for the attack, prosecutors claimed.

Mélanie G., a 31-year-old mother-of-one, was stabbed several times by the unnamed teenager outside the Françoise Dolto secondary school in Nogent, northeast France, on Tuesday.

She was rushed into critical care in 'absolute emergency' but succumbed to her injuries within two hours.

Mélanie was the mother of a four-year-old child and lived in nearby Sarcey, where she also worked as a municipal councillor, Le Dauphine reports.

She had celebrated her 31st birthday only a few days prior to the fatal attack and was described 'by all witnesses as a particularly well-liked person,' according to the prosecutor in nearby Chaumont, Denis Devallois.