Can you call an ambulance in french?

I need a paramedic = j'ai besoin d'un .... (what kind of paramedic?)

d'un infirmier, d'une infirmière = a nurse

d'un médecin = a (medical) doctor

du samu = (acronym, standing for "medical emergency services")

d'un pompier / des pompiers = a fireman / firemen (they are trained in first aid)

d'un secouriste = a first aid worker or a person trained in first-aid, (wether acting professionnally or not)