The French are famous for their politeness, except when they're not. According to the BBC, while tourists from Western cultures may laugh off the occasional rude behaviour, others can be overwhelmed: the Japanese embassy in Paris has to repatriate several of its traumatised citizens every year, with a doctor or nurse on board for support.
The article, like many others, alleges that the French are rude if you don't speak "fluent French". But in my experience (I lived 2 years in Paris), while they often prefer that you speak French, fluency is not a requirement. They were happy with my atrocious French and rarely even betrayed amusement. And many of them responded by showing off their English.
But I'm sure a conversation conducted in Engrish and Franglais can become a bit stressful after a while.