The southern reaches of the 16^th arrondissement might be considered the Wild West of Paris. Auteuil was largely countryside when Haussmann was at work on central Paris, and his ideas about tidy facades that lined up neatly never stood much of a chance here. Art Nouveau, however, with its asymmetrical shapes and writhing decorations, settled down comfortably and took root. So did a unique laboratory created by Gustave Eiffel. One summer’s day, we decided to explore.

Appropriately enough, our walk began as we came out of one of the Metro exits designed by Hector Guimard. Who needs Halloween decorations when you have lights like this?

We passed one of Guimard’s early architectural efforts at 41, rue Chardon Lagache. It was created in 1892–93 for a grocer called Louis Victor Jassedé. It is now hemmed in by other buildings, but once it would have been one of the only houses in this area, with space on all sides. In fact, when it was built, the street was called rue du Point du Jour – the street of the break of day. If that seems an odd name for a western suburb, the legend goes that this area was given the name after an 18th-century duel that took place at dawn.*

I hope Mr. Jassedé liked the house Guimard built for him. We found it a little…incoherent. Guimard seems to have been trying too hard and had too many ideas for a single structure.

Next door, near the entrance to one of those private streets known as “villas,” is a calmer 1907 Guimard construction, the Hotel Deron-Levent, built for a textile merchant. Alas, poor Charles Deron-dit-Levent didn’t have long to enjoy his mansion. He died there in 1911. However, in 1912, Guimard was called upon to design his tombstone for the Auteuil Cemetery, so Mr. Deron got to live in a Guimard structure for eternity.

Another distinctive building in the neighbourhood (not by Guimard) was the Algerian embassy on the rue Boileau, built in 1908 as the Hotel Danois (the name of its original owner). The façade was not altered in any way when the embassy moved in; it has always looked like this.

Gaston George Charles Emmanuel Danois is in some sources listed as a civil engineer and in others as a chemical engineer. He also appears to have owned – or perhaps his family owned – a dry-cleaning company (blanchisserie) in Boulogne-Billancourt. How he came to commission this remarkable residence from the architect Joachim Richard and why he wanted such an unusual design remain mysteries. Like Mr. Deron next door, he died after only a few years in the house, in 1914.

But the main  destination of our walk was farther down the rue Boileau: the Laboratoire Aerodynamique, created by Gustave Eiffel. In the early 20^th century, from his perch on top of the tower he designed, Eiffel became interested in meteorology (understandably). Over time, his study of the weather increasingly focused on winds and aerodynamics. He had been conducting research at the base of the Eiffel Tower, but the city wanted that space, so he moved his laboratory to Auteuil in 1912.

We gazed up at the building, desperately curious about what was inside. On a whim, I rang the doorbell. I figured I could at least ask if visits were possible.

After a while, a harried-looking man opened the door. No, he said, we would have inquire at the mairie to arrange a visit. For himself, he was busy right now. But he stepped back into the room to retrieve a pamphlet for us, and we followed him in. We closed the door politely behind us.

The room was set up with displays (there were even little models of streamlined cars), and since it was clearly intended for visitors, we felt a bit bolder.

Well, the man said, yes, we do sometimes give guided tours to groups, but he was very busy that day. I asked if we could take a few photographs. Erm, all right, but we had to understand that he was terribly busy.

I was starting to feel harried myself, and later I realized that several of the photos I took in haste were out of focus. But as I snapped away, I caught sight of the big central room with the wind tunnel. I pointed. Could we just take a quick look? Just for a moment?

Oh, if we must, he supposed, but he was really extremely busy. We moved towards the huge object, which turned out to be the air intake.

Norman, as a historian of technology, knew enough to ask some knowledgeable questions. In spite of himself, the man told us a bit about how it worked, and pointed to a diagram hanging on the wall.

The purpose of a wind tunnel is to determine how air flows around a particular shape. A stationary object in a wind tunnel behaves as it would if it were flying through the air. Engineers use wind tunnels to test the shapes of aircraft or cars or anything designed to go fast, or to test the performance of stable structures exposed to wind, such as bridges.

Eiffel’s work contributed enormously to early aviation and he continued his research throughout the First World War, publishing a summary of his main findings in 1919, by which time he was 87 years old. When he died four years later, aviation enthusiasts claimed that his contributions to aerodynamics vastly exceeded his contributions to civil engineering. Anybody can build a tower, they implied, but what Eiffel had learned about air flow was of greater importance.

And here we were standing where he did this pioneering work.

But yes, we understood that the fellow who had let us in was dreadfully busy and we really must go. It was lunchtime anyway and we found Le Tunnel Brasserie on the nearby boulevard Exelmans. It seemed to be something of a hangout for the laboratory staff.

We encourage you to explore Auteuil and we note that Eiffel’s laboratory may be open during Jours du Patrimoine in late September. Just don’t ring the doorbell on a working day. They’re awfully busy in there.

Text by Philippa Campsie; photographs by Philippa Campsie and Norman Ball.

*Antoine-François, comte de Coigny, was challenged and killed by Louis-Auguste, Prince de Dombes, on March 4, 1748. The prince was insulted by the count’s having mentioned that the prince’s father was an illegitimate son of Louis XIV. The duel (with swords) took place on the road between Paris and Versailles. There are varying accounts of what the count actually said and what happened that morning.