Recommend a hostel in Paris

I plan on being in Paris for 9 nights in May and I’m looking for a good safe hostel. Only condition is lockers in the same room as you sleep. Please no party hostels, I need to sleep at night! Anybody know of a good one? My price range will be around 30 euros per night.

Also can someone recommend a really tall 4- or 5-star hotel in London with gorgeous views of the city? I’ll be in London for 1 night and I figure it will be a interesting experience to stay in one of those. I did that in Taichung and I really enjoyed the view. My price range is around $250 for 1 night.

If anyone wants to toss out some destinations I just HAVE to see then feel free! I’m still coming up with my to-do list and I’m always open to suggestions. This trip is going to be so much fun!