The Spanish star secured a 7-6(5), 7-5 victory over Shelton in Sunday's final to claim his fifth ATP title of 2026 and ninth ATP Masters 1000 crown.
The triumph also represented revenge for Alcaraz, who lost to Shelton in a thrilling five-set encounter in the US Open quarter-finals in September.
Alcaraz overcomes Shelton in Paris final
The final proved competitive, with both players producing powerful tennis on the indoor hard court.
Alcaraz took the opening set in a tie-break before recovering from a break down in the second to secure victory after one hour and 57 minutes.
The 23-year-old saved six of the seven break points he faced and produced 33 winners during the contest.
His route to the trophy was not without difficulty. He had to save two match points against Taylor Fritz in the quarter-finals before eventually progressing to the final.
The victory marked Alcaraz's third title since returning from a four-month absence caused by a wrist injury. He will now turn his attention to the ATP Finals in Turin, where he hopes to secure his first year-end championship.
Claire Liu wins first WTA title in Hong Kong
American tennis player Claire Liu claimed her maiden WTA Tour singles title with a commanding 6-3, 6-0 victory over Alexandra Eala in the Hong Kong final.
Liu, who entered the WTA 250 tournament ranked 102nd in the world, produced an impressive performance against the second-seeded Filipina.
The 26-year-old did not drop a set throughout the tournament and recorded notable victories over Katie Boulter and Zeynep Sonmez on her way to the championship.
Despite the defeat, Eala enjoyed a significant milestone, rising to a career-high world ranking of 17 following an impressive 2026 campaign that included a WTA 500 title in Washington.
Linette stages comeback to win Chennai Open
In Chennai, Poland's Magda Linette claimed her fourth career title after defeating Janice Tjen 5-7, 6-1, 6-4 in the final.
The third seed recovered from losing the opening set to overcome the tournament's top seed in a contest lasting two hours and 52 minutes.
The match was also interrupted by a pollution-related delay, but Linette maintained her composure to complete the comeback and secure the championship.
The victory was particularly significant for the Pole, who finished runner-up at the Chennai Open in 2022.
Djokovic misses ATP Finals qualification
Elsewhere, Novak Djokovic suffered a surprising second-round exit at the Paris Masters after losing to Australia's Rinky Hijikata.
The Serbian, who was hoping to qualify for the ATP Finals for a 19th time, lost 2-6, 6-3, 6-2 after Hijikata recovered from a set down.
Alexander Zverev also endured disappointment, losing 6-7(5), 2-6 to Italy's Lorenzo Musetti, while Alex de Minaur failed to secure qualification for the season-ending tournament following his early departure.
Meanwhile, Venus Williams suffered her 17th consecutive WTA Tour singles defeat, losing 6-2, 6-3 to fellow American Mary Stoiana in Hong Kong.
With the ATP and WTA seasons approaching their conclusions, attention now shifts to the season-ending championships, where the leading players will look to finish 2026 on a high.