At the beginning of the play, the stage directions indicate that Garcin finds himself in a "drawing-room in Second Empire style." The "Second Empire style" refers to a style of furniture popular during the reign of Napoleon III in France, from 1852 to 1870. This style was characteristically ostentatious, grand and luxurious. I have provided a link below, which will give you more information about this style of furniture.

The stage directions at the beginning of the play also indicate that, on the mantlepiece in the room there is, in keeping with the aforementioned style, a "massive bronze ornament." When Garcin walks around the room, he also notices that there are "No mirrors" and "No windows." The implication is that there is no escape, and no way, while in the room, of communicating with the outside world. Garcin also notices the bronze ornament, which he dismisses as "that bronze contraption."

Later in the play, the audience discovers that Garcin is in fact dead, and that the drawing-room is a representation of the afterlife, or, more specifically, hell. We discover that Garcin is locked in the room forever, as a punishment for the cowardice and infidelity he was guilty of in his life. Indeed, he himself acknowledges that he is "not a very estimable person," and that he "treated (his) wife abominably." Garcin too seems to understand that he is in hell. He asks the valet where the "instruments of torture " are, and he assures him that he has "a good notion of what's coming to (him)."