Sadly, there's no announcement on the official website of the Opera House concerning this. A friend of mine (thanks!) called the box office of the National Opera by chance and this is how we all found out the the tickets for Tosca relay on November 28 went on sale two days ago. And that they WON'T the available online (at least not for the moment as the website selling them is not working) but ONLY at the box office.
So, dear Romanian fellows, don't wait too much for the electronic tickets. Pay a visit to the box office, which is open till 7pm every day. From our past experiences (Faust and Bolshoi Gala), the events involving Angela Gheorghiu get sold out fast.
I chose not to write in Romanian even if only people here are interested in this. It would have sounded bitter. English sweetened the situation.