I still struggle with description. That'll go on my grave. How's this: too much, too little, clear?
Night had fallen over the city. The wide streets close to the palace, framed by streetlights, led to the narrow lanes of the old city, where irregular lights traced the warrens of entries. The tribal enclave in the centre was dark, hidden behind walls, the glow from the great church the only thing showing there was anything in that section of the city.
This is a substantial piece of description. The second and third sentences are quite long. Okay in itself, but hopefully the preceding text sets the mood and suggests how it ties in with a character.
He took a moment, breathing in the air from the desert, sweeter in the evening and as cold as the day was hot. A wave of something – not nostalgia, he hated the city, but familiarity -- swept over him. He’d spent ten years in this city, moulding it. The fact the alleys in the centre of the city had lights in the streets was down to him; when he’d come to power that part of the city had been so poverty-stricken its residents had been left to fester in their dark houses and only allowed to live if they didn’t offend the rich residents of the central boulevards.
Ties in the scene with the character's thoughts - good.
Beside him, hunkered in the bay window of an
An? Has their position/ setting not been described in the preceding text? Also not clear if both characters are hunkered in the bay window. old church, Simone stood watch. He
Which character is 'he'? lifted his night-vision scope,
Would he need a night-vision scope if the lights are any good? focusing on the centre of the city, close to the palace. Even this late the streets were bustling, the blazing lights
I'm wondering what powers the lights, but hopefully this is made clear enough in the preceding two and a bit volumes. 
of the strip of bars and restaurants standing out against the dark gardens. He zoomed in on the palace, taking in the white walls, stark against the night sky: unchanged, unchanging, eternal. Gods, he hated the place.
