Francois Fillon, a Catholic, was picked as the presidential candidate for the French centre-right UMP party in November last year.
His declaration of faith has caused a stir in a country where the government, and elected officials, are legally not allowed to endorse a certain religion or the lack of religion, a policy known as laicite'.
He told the TF1 television channel on Tuesday: "I am a Gaullist and furthermore a Christian.
"It means that I will never take a decision that would run counter to the respect of human dignity, the respect of the individual and solidarity."
The comments were partly in response to claims he would slash welfare spending if he wins office.
He was criticised by members of both his own party and others over the remarks about his faith, with politicians urging him to keep his faith out of his campaigning.
They also accused him of using religion to win votes. Around 60 per cent of France identify as Christian.
The French presidential election takes place on April 23 2017.
