Paris in the Heat

It's been warm humid and enervating for the last couple of days, so much time has been spent sleeping and reading.
This morning we strolled back to St Eustache. We took a route along rue Rambuteau past many food shops including a couple of impressive boulangeries.
But we were particularly interested in a homewares shop which had some common items unusually executed. However to this point we've restrained ourselves but another visit might be indicated!
The reason for returning to St Eustache was Mason's sculpture of the exodus from Les Halles fruit and vegetable market that resided near the church for about 800 years before closing in 1969. We also saw a painting by Rubens of the Meeting at Emmaus.
Strolling back to the Marais there were more people on the street than on the way there. Street activity in Paris goes late into the night and the city (around our area, at least, doesn't get going until quite late in the morning so it's pleasant going out at 10am and watching the day unfold.
One of the things we notice is that there is always water being discharged into the gutters presumably to clean them. It is said to come from the Seine and presumably goes back there with sundry garbage collected on the way. It's one of the few things which is hard to take here along with the number of people who still smoke in the street. On the other hand, Parisians do most things elegantly!
Supplementary response to comment: there is a waste water management system, which is discussed at http://www.unesco.org/water/wwap/case_studies/seine_normandy/index.shtml So Paris is up to speed on treatment of waste water. In the afternoon we toddled back to St Denis to take part in a festival we saw advertised. However, it was more of an information fair, we think, perhaps to increase understanding between the many cultures coming into contact in that area. It wasn't for us!
So we got back on the metro and headed for the Champs Élysées. Most of the world seemed to be walking up this favourite boulevard which we decided was not only very crowded at this late afternoon hour but full of pizza and pasta restaurants and other incomprehensible visions such as a long queue to get into a Louis Vuitton store. Why come to Paris for that!! We decided at that point to get to the Arc de Triomphe quickly, where we found, adjacent to this great and ancient memorial, the embassy of Qatar with a glazed ceramic sculpture of a bonbon in the courtyard (see photo).
With this we retreated to the normality of the Marais where most of the people on the streets are French speakers and either gay (assumptions are being made here), Orthodox Jews or those who live or work in the area with a smattering of tourists, especially around the rue des Rosiers.
We haven't been much inclined to go out in the evening but Saturday night was an exception because it was the Nuit Blanche Paris. This is a yearly event for the last 10 years. At various points around Paris installations have been erected in church, school and many public building courtyards and people roam from one to the other between 7pm and 7am looking at them. They all involve the use of light and it has proved very popular. When we went out at about 2230 the streets were packed. The favourite as far as we could tell was one called Purple Rain (umbrella provided on entry) which had a queue for entry about 1 kilometre long. We remained in the queue for about 5 minutes because it would have taken hours to get in. Instead we crossed the road and being dragged along by the crowds managed to get a look in from afar and even a couple of photos which can't be loaded from Wendy's camera onto the iPad. The photos don't do the installation justice but they do give an idea of the crowds! It took us quite a while to get home from this point although it is normally about 5 minutes walk but it was fun...