*In and At* (a) In. Don't say: Liam has a flat at Paris. | TOEFL and Scholarship House

*In and At*

(a) In.
Don't say: Liam has a flat at Paris.

Say: Liam has a flat in Paris.

We use "in" to describe the physical location of something as part of a larger thing or place.

(b) At.
Don't say: My mother is staying in 66 Argyle Street.

Say: My mother is staying at 66 Argyle Street.

We use "at" when we're talking about an address, a public place or building (a bus stop, the Post Office, the library etc.) and cases in which the location is irrelevant but what we do there is what matters (school, the dentist, dance class etc).