I had decided that although the route continues all the way to the Mediterranean at Sète, I was going no further than Carcassonne, for a number of reasons - I didn't have time to go all the way; the towpath is reportedly unpaved after Port Lauragais and the popular guidebook by Declan Lyons rather sucks its teeth about the quality of the path; the canal becomes very sinuous so you ride a long way to make far less forward movement; there's an airport at Carcassonne with flights back to Stansted.
As it happened, I didn't need to use it, although that is at least partly because the weather had been good and the path was accordingly largely dry and mud-free.
To regain the towpath from the service area requires going back a little to the road bridge to cross to the other side of the canal, then turning right towards the east. For about a kilometre you retain the tarmac surface, but this comes to an abrupt end just after passing under the railway line, and gives way to a hard-packed dirt surface (when it's dry). Even on a Brompton though it proved rideable, albeit at a slower pace.
You quickly come to the Seuil de Naurouze - the feeder system which supplies water to the canal from a lake up in the hills to the north, down "La Rigole du Canal Midi". (There is a bike path which follows this stream all the way up to Bassin de St Ferreol, the ultimate source of the canal's water. I didn't have time for it.) This marks the high point of the Canal du Midi, with the water descending in one direction to Toulouse and the other to the sea.
The path is now all dirt or gravel, and varies considerably in quality. The very worst I experienced though was quite early on, about 2km immediately after the small hamlet of le Segala, where the path divided into two, either side of the line of plane trees, each 30-40cm wide dirt track etched into the grass. This was actually rideable, even on a Brompton, but to keep inside the narrow dirt path (where you could see any puncture hazards) and avoid frequent tree roots or stones required some deft steering and a leisurely pace. It soon gave way to a slightly broader path covered with chippings, perhaps 1 metre wide, and that in turn gave way to a wider still, perhaps 1.5m, of gravel, chippings or dirt.
In fact, it seemed reasonably clear to me that most of the route needed to be passable in a motor vehicle, because most of the locks could only be accessed by the towpath and as the locks are electrically driven, the engineers from Voies Navigables de France (VNF) need access for their vans so they can attend to do repair work. Also of course they have to be accessible to heavier machinery which comes along to cut back vegetation and make repairs to the banks. So overall the route is fairly firm dirt or gravel and about 1.5-2m wide.
In the dry: it is also pretty clear that the track could get muddy after rain, and it was not at all well drained, unlike the tarmac sections. Once or twice I had to skirt round the very edge of a path to avoid riding through puddles. However, I found that I could ride it comfortably at perhaps 20-25% slower than the tarmac sections so with a generous time allowance it was doable.
There was one point, by the Écluse de Laurens which is a pretty spectacular three-chamber lock (see short video in link below) where the notorious French "Route Barrée" signs and a high fence blocked access to the path. The reason was that some diseased plane trees were being felled up ahead - to contain the fungus which is killing the trees they burn the trees where they fall. They did however provide a reasonably clear deviation, which added perhaps 2km to the ride, and when I rejoined the towpath I was rewarded with a wide tarmac section (shared with canal management vehicles) for the res of the way into Castelnaudary.
Castelnaudary is a nice small town with a large marina basin on the canal. It is famed for its cassoulet, a casserole of beans and tomatoes with Toulouse sausage, duck confit and belly pork, which contrives to make a substantial and flavoursome meal while using only a small amount of meat. We could learn something there.
Continuing to the next small town, Bram, the path continued in the same vein - generally gravel or occasionally dirt, an occasional puddle to dodge, 1.5-2m wide, and a reasonably paced ride. Here there was a nice restaurant by the canal, L’Île des Oiseaux, whose patronne was an English lady.
Onwards to Carcassonne in much the same vein, though the canal suddenly goes from being relatively straight to really rather sinuous, so you have to ride further to get each km close to the destination. Carcassonne itself is a charming town, though smaller than I had imagined, and it looks like its economy has suffered recently with a lot of the shops in the town centre being boarded up. Also I had pictured it as a turreted and walled medieval city - yes, but the "Cité" is entirely separate from the modern town, which is neither next to it nor around it, but a good 20 minute walk away across the river. You can't even see the Cité from inside the modern town because the modern buildings are in the way.
It is quite a spectacular sight though, albeit a bit too much of a tourist trap for my taste. A kind of Mont St Michel with knobs on. At least there is no admission charge.
Some geotagged snaps here.
