I bet you thirty francs.
4 seconds sound clip from the Mr. Topaze (1961) movie soundboard.
You can hear this line at 00:08:49 in the Blu-ray version of the movie.
Quote context
[...]
- I reckon I must be the worst lodger she's ever had.
- I bet you thirty and a half francs.
- Hello. Are you ready for your lessons? Eh? Come on, up we go.
- Good gracious, have you gone through all that muck?
- You must've got up in the middle of the night.
[...]