Despite receiving mixed reviews from critics, the song was a huge success for the band after it reached number one on the charts in various countries around the world, including the United Kingdom, Ireland and New Zealand. In the process, B*Witched became the youngest girl group ever to have a UK number one. In the United States, "C'est la Vie" reached number nine on the Billboard Hot 100. In 1999, it was nominated for "Best Song Musically and Lyrically" in the Ivor Novello Awards. The accompanying music video for the song features the four girls dancing around a lush green field full of bright flowers with a puppy as they playfully tease a teenage boy.
"C'est la Vie" debuted at number one on the UK Singles Chart on 31 May 1998 and remained at the top the following week. It also went to number one in the group's home country of Ireland, as well as in New Zealand. The song went to number nine on the US Billboard Hot 100 in the week of 17 April 1999 and number six on the Australian ARIA Charts. It went Platinum in Australia for sales of over 70,000 copies. By June 2013, almost 900,000 copies of the single had been sold in the UK.
The music video for the song was directed by Alison Murray, who later also directed the UK video for "Rollercoaster". It begins with the four girls lying on the ground in a field of daisies on a sunny day. A dog is introduced into the clip next to one of the girls and the quartet then begin dancing and singing to a teenage boy in a treehouse. The girls then tie the boy to a tree and the dog chases toward him before he is magically bombarded with lipstick kiss marks all over his face. The boy is freed from the tree and the girls hose him with water and begin performing an Irish reel before lying back down in the field where they began.
In 2013, the group revealed that the song was really about sex. Keavy Lynch also revealed that Murray initially wanted Sinéad O'Carroll to look down her own jeans as she sang the line "I'll show you mine if you show me yours", but that this request was stopped rather quickly by the group's management.