What we have is an 18th century original candle lamp with sliding shade (missing the silk fabric (ready for your choice to be installed - easy). The shade adjusts up and down the square center pole with the twist of the key-like apparatus on backside, adjusting to shade the height of the candles as they burn lower. This one is curious because it came to me with 2 19th century art glass oil lamp inserts, as shown. An interesting combination, you would have option for either use. They fit with a candle-sized stem insert, just as would 2 candles. Full measurements noted on the photos.
Very good to excellent condition for age and type, these are rare. As noted, it shows a mix of 2 centuries of lighting, original 1700s candle boudoir or desk candle lamp, and later addition in 1800s of a matching pair of oil lamps. If you choose to use those, they will need wick and slender tall glass chimneys which are simple to find online. Tiny screws hold the backing to the shade frame on, and only need to be loosed and your choice of fabric (typically colored silk) cut to size and the back of the frame reset with the screws. I've shown a detail photo of it. The shade slides up or down to accommodate the height of flame of either candle or oil lamp. While not original to it, the option of the oil lamps makes them a natural 'marriage' and flexible option. Both are antique. Found in France. I have not used any solvent or cleaner on the metal, and prefer to leave the choice/decision to the next owner of this rare wonderful old candle lamp.