Newcastle let a lead slip as they went down to a bonus-point defeat by Brive.
Scott Lawson replied to the first of Thomas Laranjeira's three penalties by crossing to earn a 23rd-minute lead.
Laranjeira responded with another penalty before converting his own try two minutes before the break.
After turning round 13-5 down, Ryan Shortland's 45th-minute try, aided by two Phil Godman penalties, put the Falcons 16-13 ahead, only for Venione Voretamaya's converted try to win it.
Godman missed three kickable penalties, the last of them, after Laranjeira's third penalty had levelled it again at 16-16, shortly before Voretamaya's matchwinning try.
Newcastle's bonus point, coming on top of last weekend's in Romania, was enough to keep them top of Pool 3 after two matches.
The Falcons made eight changes to the side that narrowly beat Bucuresti, Scotland hooker Lawson, who broke a hand in July after signing from London Irish, coming in for his debut.
But former Lions scrum-half Mike Blair was rested, so did not face the club he left in the summer.
Brive: Ferreres; Mafi, Galala, Laranjeira, Voretamaya; Sola, Neveu; Lavergne, Ribes, Leupolu, Lebas, Pinet, Laurent, Briatte, Murphy.
Replacements: Hireche for Briatte (20), Da Ros for Lavergne (50), Coetzee for Ribes (50), Laval for Leupolu (50), Kusiolek for Neveu (61), Delage for Galala (63), Neisen for Ferreres (66), Uanivi for Lebas (66),
Sin Bin: Pinet (21).
Newcastle: A Tait; Cato, Powell, Fitzpatrick, Shortland; Godman, Fury; Vickers, Lawson, S Wilson, McKenzie, Tomes, Barrow, M Wilson, York.
Replacements: Shiells for Vickers (50), Tomaszczyk for Lawson (50), McGuigan for S Wilson (50), MacLeod for McKenzie (59). Pilgrim for Shortland (61), Hogg for Powell (63), Hodgson for Godman (71).
Not Used: Brown.
Sin Bin: Tomaszczyk (58).
Referee: Dudley Phillips (RFU).