The €5,000 event drew 188 players to the famed Aviation Club De Paris last week.
Coming off a win in the Aussie Millions $100k Challenge and a runner-up finish to Hall fo Famer Erik Seidel in the series' $250k Super High Roller last month, Trickett sat second in chips with ten players remaining.
However, he doubled up three opponents in the play down to the final table of eight and fell to seventh in chips heading into Tuesday's final.
The Titan Poker pro managed to move up the pay scale, but was downed sixth when he ran pocket fives into Jean-Louis Tepper's nines.
Trickett added €43,545 to the amazing $2,892,889 he's earned in 2011 already.
Three-handed, Tepper had the lead, but Nikitina doubled through him to take control.
After Tepper busted, Nikitina entered heads up with small chip lead before Alexandre Brivot doubled up to cripple her.
However, she came from behind twice in all-in pots to take the lead back and eventually put Brivot away to collect the €243,830 first prize.
Here's how the final table finished up in what was officially The World Poker Tour National Series Euro Finals Of Poker Diamond Championship €5,000 main event:
1. Natalia Nikitina €243,830
2. Alexandre Brivot €174,170
3. Jean-Louis Tepper €113,210
4. Benjamin Pollak €69,670
5. Tobias Wagner €52,250
6. Sam Trickett €43,545
7. Ingo Paulus €34,835
8. Nicolo Calia €26,120