The very common French expression ah bon ? is really more of an interjection and can be translated in many different ways. It is such an easy expression, but it can make you sound so French! We use it all the time. The most common translation is “really?” but these are some clues that will help you.
Use ah bon ? when you want to:
Don't be fooled by bon, it doesn't mean "good" here. So ah bon ? doesn’t mean “oh good” and it can be used when talking about both good and bad things.
You’ll never guess! He’s getting married tomorrow. - No way!
J'ai vu un film intéressant hier. - Ah bon ?
I saw an interesting movie yesterday. - Oh, yeah? You did?
Ils ont déménagé après le décès de leur père. - Ah bon ?
They moved after their father died. - I see.
Use ah bon ? when you want to:
- indicate surprise
- indicate an understanding of what was said
- indicate an interest in what was said
- show a desire to want to hear more of the conversation
- show a desire to contribute to the conversation
Don't be fooled by bon, it doesn't mean "good" here. So ah bon ? doesn’t mean “oh good” and it can be used when talking about both good and bad things.
Examples
Tu ne devineras jamais ! Il se marie demain. - Ah bon ?You’ll never guess! He’s getting married tomorrow. - No way!
J'ai vu un film intéressant hier. - Ah bon ?
I saw an interesting movie yesterday. - Oh, yeah? You did?
Ils ont déménagé après le décès de leur père. - Ah bon ?
They moved after their father died. - I see.