Bienvenue Garoolgan,
Well, as there are only three (or is it down to two) actual manufacturers of External Hard Drives (EHD) - brand names don't mean they make the drive - I suggest you make a short list of your needs.
For example, Mains-powered or bus-powered (i.e. powered via the USB port on your Mac). Given that you are seeking a very modest storage capacity, this will almost certainly be USB-powered. USB 3? Target price? - you get what you pay for generally. Does it need to be "rugged" for heavy-duty carrying around? Or something you are likely to keep at home or carry carefully?
Amazon (France) has a huge selection and if you filter according to the answers to the above questions, you will find plenty to choose from. Then, read the reviews very carefully.
Of course, you can use the Internet - Western Digital (black); LaCie, (I'm a fan, but many others aren't); Seagate (I'm not a fan, but some are).
This Link may help a bit:
http://www.techradar.com/news/computing-components/storage/external-hard-drive-1292181
Ian