Aeroflot does not fly to Lisbon. That is sad because I cannot use my frequent-flyer bonuses.
A discount offered by TAP for this conference is not available for travelling from Moscow. There are no direct flight from to Lisbon. TAP search suggests to have a change in Munich, thus only half of fly segments are handled by TAP, another half by Lufthansa.
Flight Moscow—Munich—Lisbon—Munich—Moscow costs 417 EUR (January price).
Travel.ru informs that that itinerary is incorrect, and TAP is going to fly directly from Moscow since 10th of June.
Tip: there are no Moscow in the list on front page at http://www.flytap.com/. Click "Advanced Search" first, Moscow appears there.