梦巴黎的四年回首难忘
[mèng bā lí de sì nián huí shŏu nán wàng]
This username translates to 'Looking Back at Four Years in Dreamy Paris with Unforgettable Memories.' It suggests that the user spent four meaningful years in Paris, which left an unforgettable impression, filled with beautiful and perhaps bittersweet memories.