Carter posted the apology on Facebook after being caught drink-driving in Paris.
"No excuses - I made a massive error of judgment and have let down my club, my fans and most importantly my family," he wrote.
"I will have to now let the police/court process run its course and face the consequences. I am just glad no one was harmed. Sorry."
Carter, who plays for the Racing 92 club in Paris, was nabbed by French police, while driving near the Champs-Elysee in central Paris on Wednesday night.
He reportedly did not have his driver's licence with him and had a blood alcohol level of 0.98g per litre, above the limit of 0.5g.
The drink-drive limit is the same in New Zealand, although it used to be 0.8g.
According to French media, Carter was not held in custody or put in a sobering cell, but his car was impounded. He will reportedly appear in court.
France-based Radio Sport correspondent Catherine Field warned that French drink-driving laws were much stricter than they have been in the past, when the wine-drinking culture was prevalent.
"There's a real feeling here over the past four or five years that drink driving isn't a good thing to do any more," she said.
"People have realised that picture of France of 30 years ago, when you could go out and have a great lunch and a pastis, and then drive home ... those are the old days. Now, it's very strict.
"[Dan Carter] will probably undoubtedly lose his licence. What type of financial penalty will again be up to the judge."