Newcastle lost their unbeaten record in the European Challenge Cup as Stade Francais scored a late try to win a thrilling Pool 3 tie 31-24.
But Dean Richards' young side claimed a losing bonus point at the Stade Jean-Bouin in Paris which might prove crucial in the final reckoning.
Both sides made seven changes from last weekend's contest at Kingston Park which the Falcons won 30-23 to boost their hopes of qualification from a pool also containing Newport-Gwent Dragons and Romanian side Bucuresti.
Stade's forward power, especially at scrum time, helped them to four tries and a bonus point before half-time after Argentinean centre Juan Pablo Socino had profited from a Mark Wilson charge down to score and give the Falcons a 7-0 lead.
Krishnan Inu, Djibril Camara, Mark Williams and a penalty try put Stade in control but Newcastle full-back Simon Hammersley was proving dangerous with ball in hand and he finished a superb Falcons move to make it 24-14 at the break.
Falcons reduced the deficit when No.8 Wilson wriggled over from a quickly-taken tap penalty and Rory Clegg added the extras before levelling matters with a 25-metre penalty.
But with both sides down to 14 men due to yellow cards Stade claimed the decisive score from a rolling maul with hooker Remi Bonfils believed to be the man at the bottom of a pile of bodies.
Stade's five-point haul means they trail Newcastle by five points with two rounds of matches remaining, while the Dragons are four points behind the Falcons with a game in hand.