We see it before, actually, in the episode where Carrie browbeats Charlotte into getting the money for the apartment down payment.
Carrie being bored and lonely in France was just beyond stupid. I realize this was before social media, but didn't she make any friends in her French classes? And if not, all she had to was contact the embassy and/or consulate and ask about any social groups or clubs for American citizens living in Paris, or ask about any events that she could have attended. She could have easily made a friend or two, but this being Carrie, she probably was waiting for them to