Verified answer

It means "French people are really f***ing rude". The letter "d" at the beginning of the sentence a homophone of the word 啲, which is used to describe things or people in numbers. The underscore near the acts as a "insert profanity here".

d法國佬 - French people

真係好 - Are really

_ - Insert profanity here

冇禮貌 - lacking manners

Nothing sexual is implied in this sentence. Unfortunately, I don't know what "Hi Hi LAI" means, sorry.

the french person has really good manners.