Yes, you can use both “city center” and “downtown.” They mean almost the same thing, but the grammar is a little different.
Downtown
- Often used in American English.
- It can be used without a preposition.
Example:
- The new restaurant opened downtown last week.
City center
- More common in British English.
- It usually needs “in the” before it.
Example:
- The new restaurant opened in the city center last week.
So both are correct, but the structure of the sentence changes slightly.
But, you cannot use them interchangeably in grammar.
Examples to show the difference:
Correct:
• I work downtown.
Incorrect:
• I work city center.
Correct:
• I work in the city center.
So:
**Meaning = interchangeable
Grammar = not interchangeable**