The sentence can be corrected for subject-verb agreement by changing "are" to "is," since "city council" is typically treated as a singular entity in American English. The corrected sentence is:
"The city council is meeting on Tuesday night to discuss the new park."
If you're using British English, "are" can be considered acceptable because "council" refers to a group of individuals. In that case, the sentence could remain as is, but it's more commonly revised for clarity in American English.