The first is why the police inspector picked on our man (Jef Costello). Only one witness out of six identifies him as the shooter. Supposedly they had rounded up ten of the usual suspects from all 40 districts. Now it could be that none of the witnesses picked any of the other suspects, but with six witnesses and 400 suspects I would think there would have to be some false positives. But the inspector is sure our man is the shooter and proceeds to try and prove it.
The girlfriend provided his alibi and inspector wants to break it, so he takes a couple of his coppers over to her apartment to search it. While they are searching it, he proceeds to attempt to intimidate the girl into giving up her boyfriend. He is very convincing, but she is one tough cookie. She doesn't even quiver, she sticks to her story and sends the cops packing.
Then there is the caged bird in Jef's apartment. When Jef returns to his apartment after the cops had broken in to plant a bug, the bird seems to be missing some tail feathers, and seems a little agitated. Same thing again when Jef returns again and the errand boy is hiding in the kitchen with a gun. It's a little hard to tell because, I mean, it's a bird, it's tweeting and hopping around anyway. Is it tweeting and hopping more than it was? Is it really missing any feathers? I mean, I didn't pay that much attention to it the first time we saw it, other than to notice that the director seemed to be spending an awful lot of time looking at this stupid bird.
At the end our hero falls on his sword. Not literally, but the effect is the same. The first time I saw it, this didn't make any sense to me, but then the title didn't make much sense either. Now I think I have an explanation. The nightclub singer sees him just after he has done the job he was hired to do, which was to kill the manager of the nightclub. She gets called as a witness but then denies seeing him. As the movie rolls along, our hero figures out that the guy who hired him, and then tried to kill him, is her keeper. He has a shootout with his client and the client ends up dead, which means the cops are going to connect her to this whole thing, which will put her in hot water for lying. So our hero lays down his life to deflect the ton of trouble that would come crashing down on her. That's the way I figure it anyway. Kind of a big sacrifice for such a small favor, but I guess that's why it's called Le Samouraï. Crazy nips.