Hotel Adler

Address: Niddastraße, 65, Frankfurt. A quick check on the map can help confirm the entrance and the easiest approach.

Looks like they're open every day, so you don't need to worry about timing your visit around a closed day.

According to available data, this is a hotel. Expect a private room, a reception desk, and the usual hotel services. Star rating, amenities, and recent reviews will give a clearer picture of the standard than the label alone.