Here they take on the urbanists, insults from Constant in ‘Unitary Urbanism’ a lecture from 1960:

The failure of modern urbanists can be attributed to their opportunism, their passive attitude to the problems confronting them, their uncritical deference to an obsolete cultural convention, to the existing image of society. What nowadays counts for urbanism confines itself to the more or less aesthetic solution of current socio-economic problems; for the most part housing and traffic problems. For pragmatic reasons, that is for the sake of a quick provisional solution, urbanists isolate these problems from the totality of social life, they see them as detached from the cultural issue. (112)

Here is the proof that today’s urbanists are indeed to blame for the failure of the modern city as a human habitat, for the disappearance of a social space in which a new culture could arise. (113)

Then there are the existentialist digs — Sartre, Camus and Simone de Beauvoir among others lived on Saint-Germain-des-Prés, frequented the two cafes there, Café de Flore and Les Deux Magots. Hemingway and Picasso hung out there too, but maybe not together. These cafés became centres of tourism where Americans waited anxiously for wisdom to fall into their laps (only the coolest people know that Baldwin also wrote much of Go Tell It on the Mountain here).

A certain Saint-Germain-des-Prés, on which no one has yet written a word, was the first unit working at the scale of history on this ethics of dérive. This egregore, secret until now, is the lone explanation for the enormous influence that three blocks of houses have exerted over the world, and that people have tried to rationalize through the insufficient fields of clothing and song, and more stupidly through questionable aptitudes for prostitution… (Gilles Ivain (aka Ivan Chtcheglov) Internationale situationniste no 1 (June 1958), p 41)

But the very best are reserved for Le Corbusier, they are delicious:

The modulor Protestant, Le Corbusier-Sing-Sing, the dauber of neo-Cubist smears, is making the “machine for living in” work for the greater glory of God, who created carrion and crows [corbusiers] in his own image
‘Skyscrapers by the Roots, Lettrist International, Potlatch no. 5, July 20, 1954 (p44)

and this:

We leave to monsieur Le Corbusier his style that suits factories as well as it does hospitals. And the prisons of the future: is he not already building churches? I do not know what this individual–ugly of countenance and hideous in his conceptions of the world–is repressing to make him want thus to crush humanity under ignoble heaps of reinforced concrete, a noble material that ought to permit an aerial articulation of space superior to Flamboyant Gothic. His power of cretinization is vast. A model by Corbusier is the only image that brings to my mind the idea of immediate suicide. With him moreover and remaining joy will fade. And love–passion–liberty. (35)
‘Formulary for a New Urbanism’ Gilles Ivain (aka Ivan Chtcheglov) Internationale situationniste no 1 (June 1958)

You realise Debord is actually the least exciting of insult-writers:

Since Le Corbusier has made of his work an illustration of and a powerful means of action for the worst oppressive forces, this work–certain of whose lessons should however be incorporated into the next phase–is promised a complete bankruptcy.
Statement by Lettrist International Delegate to the Alba Congress – Guy Debord (92)

There are more, but I tired of the exercise…

[these translations from the wonderful compilation by Mcdonough, Tom. (2009) the situationists and the city. London, NY: Verso.]