'This has changed my life, it is hard to take in at the moment, but I know for sure that my life is changing,' said Lima, who picked up a European Challenge Tour win last week. 'It has been an unbelievable two weeks for me, firstly with my victory in Spain last week, and then to win here is just a dream come true for me.
'I don't know what my schedule will be like now, I just haven't had time to think about it, but now I will definitely go to the Open de France and play on the European Tour, who knows, it could be three wins in a row.'
Tadini's closing bogey dropped him to 4-under-par 280, after a final round 69. David J. Geall, one of six leaders after the third round, posted an even- par 71 to end the tournament at 3-under-par 281. Simon Dyson, James Hepworth, Iain Pyman and Carl Suneson finished one stroke further back at minus-2.
Lima posted three straight rounds of even-par 71 to enter the final round in a tie for eighth. He was steady to start with three straight pars to begin his round.
The 22-year-old then birdied the par-3 fourth. Lima came back with consecutive birdies from the sixth to get to 3 under. The Frenchman then birdied the ninth for the third time in four rounds to move to minus-4.
Lima then ran off three straight pars from the 10th on the Val Course at Aa Saint Omer Golf Club. He stumbled to his lone bogey at the par-4 13th. Lima came right back to birdie the 14th for the fourth time in four rounds.
Lima then picked up a birdie at the 16th to get to 5 under. He parred the final two holes and had to watch Tadini, who he was tied with, finish.
Tadini stumbled to a three-putt bogey from 40 feet out at the last to drop one shot behind Lima. The bogey cost Tadini a chance at his first European Tour crown.
'Obviously I am disappointed to have missed the putt on 18, but I think that the money I have won here, and at the start of the year in Costa Rica will bring me close to securing a place on the European Tour next year as one of the top-15 Challenge Tour players,' Tadini said.
Tadini began the day at minus-2. He started quickly with birdies at each of his first two holes, then parred the next six holes to remain steady at minus-4.
The Italian birdied the par-5 ninth for the third straight day to get to minus-5 and take the lead. Tadini looked as though he would remain there to force a playoff as he parred eight consecutive holes from the 10th.
Massimo Florioli and Jean-Francois Lucquin, who held a share of the lead entering the final round, each struggled to rounds of 3-over 74. They ended the event at even-par 284, where they were joined by Johan Skold (71).
Didier de Vooght, Sebastien Delagrange, Jamie Little, Pasi Purhonen and Murray Urquhart ended one stroke further back at 1-over-par 285.