Je suis à la maison de Lucie

Question

BonjourJe suis à la maison de Lucie*I wonder what is the reason on its incorrect.Is it because that it's too formal?Merci~

Céline Pickard · Accepted Answer

Bonjour Gene,
It is not a question of the statement being formal or informal but rather about what is normal usage in French. Saying, "à la maison de Lucie" sounds unnatural to French native speakers.
To express "at/to [someone's] house", you use "chez [name]":

Je suis chez Gene = I am at Gene's house
Je vais chez Gene = I am going to Gene's house

Chez = at someone's place (French Prepositions)
Also, to express being "in/inside [someone's] house", you use the preposition "dans":
Je suis dans la maison de Gene = I am inside Gene's house
En vs Dans with locations (French Prepositions of Location)
I hope this is helpful.
Bonne journée !