We just returned from a 6 night stay in Paris. We stayed at the Hotel du Nord, 47 rue Albert Thomas, in the 10th arrondisment. I just posted a full review on tripadvisor.com.

The rooms are tiny, but we only paid 84,50 euros/night - and we had a private bath. The neighborhood is very convenient to everything. The staff at the hotel were all very kind and helpful. The hotel does not have A/C, so I would not stay there July-August.