* note at the bottom of this blog you can watch the entire scene, otherwise I'm going to explain it all right now..
The set up is that Edith is talking on the phone with her lover Marcel, who is due to return from out of country via ship, yet she insists that he should fly in the next morning because she misses him tremendously. 
He agrees making it extra romantic. 
The next scene we see Edith taking a sleeping pill and gets into bed, camera fades out.
This is where it gets good! Camera fades in the next morning and Edith is awaken by Marcel. "You sleep late when I'm not here" says Marcel; which I think the director is referring to the sleeping pill Edith took the night before, and is also hinting for what is about to unravel. 
"I'll make coffee, you stay here" Edith tell Marcel. She jumps out of bed as the camera followers her down a corridor. I absolutely LOVE this screen capture showing Edith fluffing her curly hair.. its perfect. Beyond that, when first watching this scene, I found it odd that Edith told Marcel to stay in bed. I wondered why not accompany Edith to make coffee together, it'd be more romantic?.. Yes, it would.. but for this scene, its necessary for Marcel to stay in bed!
The camera continues with Edith to the kitchen where ironically the coffee along with toast is already made? Theres also a character awkardly sitting at the dining room table. Edith had the right to ask "What are you doing here" before she cheerfully walks the food platter back to Marcel, who is still waiting on her bed. 
(haha) I captured this clip (below) and you can actually hear me say (god this is perfect).. hahaha.. I didn't know I recorded myself. Coffee is brought to Marcel, they kiss a few times, and she tells him she has a gift for him before walking back down the corridor.
I love this contrast of how Edith talks sweetly with Marcel and then with everyone else she raises her voice and insults them. Here the camera continues to follow Edith, where we see a guy (guard perhaps) thats standing awkwardly.. "you need sun, You're pale" Edith tells him as she passes him. To the audience we shouldn't think much about this, but in hindsight.. its perfect; because little do we know, Marcel is actually dead.. and perhaps the guard character looks pale because he already knows the news about Marcel.
We discover that the present for Marcel is a Cartier watch, and Edith is looking for it.. Edith calls out Ginou asking if she knew where it was. Edith begins to get impatient.
Theres clearly something wrong, another person awkwardly presents herself. "whats gotten into you" Edith yells out and she continues to frantically look for the watch. Edith almost becomes sloppy about looking for the watch, almost like her "sleeping pill" has warn out and shes not dreaming anymore. 
Edith continues and the camera follows.. Yet again, theres another person awkwardly stands at the end of a hallway. Clearly, something tragic has happen.. 
Edith now is in a room with three others.. "What is wrong with all of you" she yells out and continues to look for the watch. At this point she knows something is up but she insist to look for Marcels watch.
"What, is it Marcel?" she yells. "The plane crashed", some guy says. Edith, obviously is in shock but the expression on her face tells us that she doesn't believe it- obviously we saw them interact. Edith walks back to her to her room passing a woman who is crying (perfect).. 
Her room is empty. it eventually finally sinks in.. Everything that happened in he beginning of the scene was all an illusion! It all comes together, the audiene as well as Edith discovers together, which is what I think makes this scene strong!. It's perfect that all the "awkward" people were in fact suppose to be awkward because they knew Marcel was dead.. The fact that she took a sleeping pill the night before ties into the the fact that she woke up late; the idea that in the beginning of the scene she was cheerful which progressed with reality to impatiently angry made this entire scene PERFECT.
This image here litereally brings me to tears. It is real.. the emotion is real, the situation makes it all feel so damn real! Perfect.
whats worst, and also perfect, a sad song is played during the rest of scene as she frantically shouts "Marcel!!"
Edith continues to cry, music gets louder, audio is mute and.. then, just as if God opened the gates of heaven, the icing on the cake is when the set extends to a stage where she transitions to performing the actual song.. which is obviously about Marcel.. Now, we as the audience, can feel the impact of emotion that Edith has while she sings the song. Her voice is not enough to tell us what she feels- we needed to know what she was thinking. How else could the director tell us that she was thinking about Marcel?. fucking PERFECT SHIT!! im crying. AND!- it was all done with one continuous camera.. WTF! amazing!
Here's the entire scene.. forgive the voiceover where u can hear me express my love for it. lol