There's a certain degree of romanticism associated with an underground resistance. A secret network of brave fighters banding together to topple and drive out the hated occupiers, operating behind enemy lines in constant danger, and refusing to surrender is the type of tale told to swell patriotic fervor and inspire nations.
Army of Shadows (1969) is directed by Jean-Pierre Melville, himself a member of the French resistance during World War II. I don't know how much of his own experience is reflected in the film, but it is not a glamorized portrayal. Set in late 1942 in Nazi-occupied France, the movie shows us no explosions, midnight raids, firefights, or even a real sense of eventual triumph.
We see the men and women of the Maquis, the name of the French resistance, engage in acts of subterfuge, relying on false identities, disguises, and forged paperwork and knowing they are probably going to be compromised, tortured, and killed. It is a bleak, lonely, and desolate life.