Discuss and learn French: French vocabulary, French grammar, French culture etc.
Just put the name and don't worry about it. The surname "Bastard" isn't as uncommon in French as it is in English, and at the end of the day, that's the name (it stems from a time when the word "bastard" was more of a scientific word than a 'swearword'). People doing their internship in the Austrian town of Fucking will be struck with the same dilemma.
If they're not familiar with French surnames, the person reading the CV might have a little chuckle to themselves, but I don't think it's such a big deal.