profitez de la Happy Hour et soyez prudent (The term 'happy hour' is used in France, while nobody says "l'heure heureuse")
joyeux Ramadan
je ne suis / tu n'es / il, elle n'est plus heureux / plus heureuse
I would say: très heureux I'm not sure it's spelled right though... you can also just say heureux
There are basically two words for happy in French -- content and heureux. Content is more often used for a simple, immediate emotion, while heureux is more often used in a general, more profound...