As a single traveler, what transportation would you recommend post concert? I'm staying in Rue Cler area.
The Metro is safe at that hour, and there will be lots of other people - single or in groups - using it to go home. Protect your valuables, don't over-indulge, avoid talking to strangers, and you'll be fine.
If you can get to the Metro by 1:30 AM, you'll have time to get to rue Cler. Walking from the Metro to your hotel will not be dangerous at all, the streets will be very quiet.
The other options are to look for the nearest TAXI stand or try to flag a taxi on the street. If the light on top is green, the taxi will be available. The fare will be extremely expensive - probably upwards of 70 EU.
I've seen Madonna twice at the Stade de France and the metro is DEFINITELY the only way to go. It does get packed, but it was actually much better than I anticipated.
Don't bring bottled water. They make you take the cap off. Seats here leave a lot to be desired. If there wasn't a jumbotron, you wouldn't see a thing. But Parisian audiences are AMAZING
We did a U2 concert there in 2010 (good times). It would be the biggest we've ever been to - Wikipedia says 96,000 people (that's about 8 times the population of the town I live in! All in one stadium!). It had to have been one of the most orderly concert leaving....many people used the metro (we were in the Montmartre area) and it was fine. There seemed to be lots of trains lined up - the only thing I remember is many people seemed to crowd on by the doors but didn't move into the train car itself - so once we squeezed past the people at the door, we were actually able to find a seat...so even if the doorways are crowded, try to squeeze in and maybe you'll find a seat.
You could also use Uber, but that will be very expensive and the pick up spot may be relatively far from the stadium. I took an Uber home from a Beyoncé concert here in California and they had 8X surge pricing in place and the Uber car was a long walk from the stadium. I can't imagine they would not do the same thing in Paris. I recommend the metro if it is still running after the concert (and it should be because Beyoncé does not do encores).
I would definitely not advise Uber. If you take a normal Parisian taxi, the fare will already be astronomical.
Take the Metro with everyone else.
I would also not recommend either Uber or a Taxi from the concert as the traffic around the stadium will likely be extremely THICK. If using Uber, you could get nicked by "Surge Pricing" and the ride could cost you a small fortune. Use the Metro.