Hotel Diana,, I have not stayed there, but I have walked by it,, and its in a very conveinent area,, on a quieter street, but very close to the busy Latin Quarter area.
Also, Hotel Eugenie,, may be out of your price range , but I have seen three of the rooms and they were fine,,clean, reasonable size, good bathrooms and a/c etc. Location is as central as anything in Paris,, you will be right by river( 1/2 block up) on a tiny narrow and busy street, with tons of cafes and shops all around you.
Hotel Du College Du France is well thought of,, i haven't stayed there.
I would definately look outside of the Rue Cler area,, sinces its only one street,, and not that central anyways.. yes, its close to ET,, but how many times can you go there??