Is it Halal or Haram to deal with a non-Muslim real estate agency to find you a condo or a house and to buy?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

There is no harm to work in real estate agencies or other fields owned by non-Muslims as long as the transaction itself does not contradict the Islamic Shariah.  The Prophet (Sallallahu Alaihi wa Sallam) and his companions used to deal with Jews and other non-Muslims in trade, taking loans, etc.

However, it is desirable to try to benefit Muslims. Hence, it is preferable to deal with Muslims to strengthen them rather than strengthening non-Muslims.

Allah knows best.