Bonjour, Madame
I would like to say that your query leads to a lot of questions :
Is noise a problem; if such is not the case, you can search for any piston compressor in a DIY shop ( Kingfisher ? ); the item will already be fit with a regulator, auto shut off, moisture trap, etc... BUT you'll certainly hear it while in use; on the opposite, you can get a silent compressor in a hobby shop, an art store, even in a DIY shop( one of my compressors comes from here ) but they'll tend to be more expensive than the first option ( a French proverb says that Speech is Silver and Silence is Gold ); on this option, you'll probably get the whole array of "accessories" ( regulator, moisture trap, etc ...) to get an idea of the noise, the motor of this kind of compressor is the same as the one from your frig, or bigger; the third option is what I would call discreet compressors and they don't make a lot of noise, but they can't honestly be called silent. If you can afford, choose a silent one; you can take a look at ebay, but don't forget that your compressor must be in 240 VAC so you had rather search in european ebay sites ( ebay Germany has a lot of these things regularly )
Feel free to ask for more precisions
PS I forgot to say that an air storage tank is strongly recommended; this may take part of the compressor, or not.