
Dear Readers:
You guys are awesome and way too clever. I am overwhelmed by the number of you (46!)who responded even without the promise of a halfway decent prize. Could it be that you are just a wee bit competitive?
At any rate, most of you correctly discerned that the colors for the two lines were inverted. Line 1, the most traveled line in the system thanks to both locals and tourists, should be yellow and line 6 should be green. The real question is this: if so many of you had no trouble detecting the error, what's up with the folks who work for the RATP who mounted it?
Here's the correct version, placed not 10 meters from the one in error:

And now what you've all been waiting for. The glory of winning goes to Laura for coming in with the first correct answer at 9:00 am Paris time. You might enjoy
Laura's blog about Paris if you read Italian; or if you're like me and can only pick out a few words, you can just enjoy the photos. Congratulations, Laura! Since you already live in Paris, I'm assuming you don't want an Eiffel Tower keychain and you can buy your own Speculoos spread. Can I bake you a batch of American brownies or send you some tunes? E-mail me at justanotheramericaninparis@yahoo.com and we'll figure it out.
As for some of the other guesses, it's true that line 6 shows only one terminus rather than two. But that's because the Charles de Gaulle stop is the end of the line on the 6, thus there's only one direction you can go on that line from there. Someone else noted that line 2 is missing. While it's true that line 2 does go through this station, you have to take another corridor to get there from the RER tracks.
Well played all. Perhaps there's another contest in this blog's future. If so, I promise to post it later in the day so those stateside have a fair crack at being first to respond.