Mandzukic became the first player to score an own goal in a World Cup final when he headed Antoine Griezmann's free-kick into his own net in the 18th minute.
This was also and unfortunately 12th own goal of a record-breaking tournament in Russia.
Griezmann's free-kick brushed the top of Mandzukic's head and sailed over his own goalkeeper to give France a 1-0 lead at the Luzhniki Stadium.
However, Ivan Perisic levelled 10 minutes later but Croatia's joy was shortlived as Antoine Griezmann converted a penalty in the 38th minute to France a 2-1 half-time lead.
A short while ago, France was leading 4-1.