If you don't have your user guide any more, you can
view, but not download it here:
http://products.bose.com/pdf/customer_service/owners/og_awmsii.pdf
Bose has blocked the download of the .pdf file for whatever reason.
If you check it you will see that it is compatible with international AC voltages (220-240) but France uses a different AC receptacle than the US so you will need the correct power cord.
As far as frequency bands; Europe uses much the same for AM & FM but some bands not used in the US won't be available with the Bose.
Because the user is supposed to be an idiot, they have very little detail in their manual besides what is necessary to operate it, they do not specify whether the power supply is auto-switching for different AC voltages or not. Most modern electronics uses a type of supply that will accept anything from 100-240 VAC and that kind of supply doesn't care much what the line frequency (50 or 60Hz) is since they do not use low frequency AC transformers.
Typically, their customer service phone line is answered qjuickly and by knowledgeable people so I recommend you call them with the request for the needed AC power cord and ask them about the means of accommodating French line voltage.
You didn't mention where you live so you will have to check for the proper current toll-free number on page 27 of the online user guide linked above.