The guide
Why this stretch and not another
The canal is four and a half kilometres long and only about six hundred metres of it are worth a session.
The useful part is where the footbridges cluster: three iron crossings, two locks, plane trees on both banks and a run of pale nineteenth-century facades behind them. Everything a photograph needs is within a ten-minute walk, which means an hour here is an hour of photographs rather than an hour of commuting between them.
North of that the banks open out and lose their character; south, the canal disappears underground.
The hour
Late afternoon, when the sun runs along the axis of the water rather than across it. The whole surface lights up, the ironwork goes into silhouette, and the reflections do the work that would otherwise need equipment.
That effect lasts about an hour and it moves through the year. In June it is at eight in the evening; in December it is at three in the afternoon, and the canal is deserted, which is its own argument.
Crowds, honestly
From May to September this is one of the most popular places in Paris to sit outside with a drink, and by six in the evening both banks are full of people doing exactly that.
They are not in the way of a good photograph — a canal bank full of Parisians is a truer picture of the place than an empty one — but they make a posed session awkward and they make a family session with small children genuinely difficult.
Mornings are the answer if you want the place to yourself. Before nine, even in August, it is quiet.
What it suits
Couple sessions above all: the scale is intimate, the walking is flat, and nothing about it feels like a monument.
It also works well inside a wider Paris session as a contrast to somewhere grander, and for families, provided the hour is early enough that a pushchair on a narrow towpath is not a problem.
The tenth arrondissement is a short walk from the Marais, so it combines easily with a second location. Prices are on the rate card.