What city should be suing the non-paying tenant?

The real estate rule says that the suit must be filed in the domicile where the property is rented. That doesn't matter if you live there or not, it also doesn't matter if the tenant lives in your city or not. So the correct municipality is where the property is located, of course there are some rules which may be different, especially if you are evading this summons, but there is a correct location.