French President Emmanuel Macron defeated his far-right rival Marine Le Pen on Sunday by a comfortable margin, securing a second term and heading off what would have been a political earthquake.

Cheers of joy erupted as the results appeared on a giant screen at the Champ de Mars park at the foot of the Eiffel tower, where Macron supporters waved French and EU flags. People hugged each other, danced and chanted "Macron!"...