Royals reliever Jake Brentz (0-3) walked four straight batters to open the eighth inning. His bases-loaded free pass to Julio Rodriguez allowed Donovan Walton to score the go-ahead run. Jesse Winker then drove in two runs with a double to make it 10-7 before France homered to center field.
France, who had five RBIs, became the first Mariners player with five or more hits in a game since Dee-Strange Gordon on May 1, 2018.
Seattle had seven extra-base hits. J.P. Crawford had two hits, including a two-run homer in the first.
Diego Castillo (1-0) pitched a perfect eighth for the win.
The Royals entered the seventh trailing 6-4. Carlos Santana tied it with a two-run homer to right field before Edward Olivares gave Kansas City the lead with an RBI double.
France drove in a run with a single in the bottom of the inning.
Abraham Toro’s ground-rule double in the third drove in Eugenio Suarez and put the Mariners up 5-1. Toro was the last batter to face Royals starter Kris Bubic, who gave up seven hits and five runs in two innings.
Kansas City scored three times in the fifth.
With the bases loaded and one out, Hunter Dozier singled to score Andrew Benintendi. A throwing error by Crawford at shortstop allowed Salvador Perez to score. Bobby Witt Jr. then drove in Santana with a single.
A double by Suarez scored France in the sixth to give the Mariners a two-run lead heading into the seventh.
Seattle starter Matt Brash pitched 4 1/3 innings, allowing five hits and three runs.
The Mariners acquired outfielder Stuart Fairchild from Arizona for cash. Fairchild will report to Triple-A Tacoma. Infielder Kevin Padlo was designated for assignment.
Royals: Perez was hit in the hand by Yohan Ramirez’s fastball in the seventh inning. He remained in the game. … OF Michael A. Taylor got the night off. He’s expected to return to the lineup for Sunday’s series finale.
Mariners: None of the players or coaches who tested positive for COVID-19 have rejoined the team yet.
Royals: LHP Carlos Hernandez (0-0, 7.27 ERA) makes his third start of the season Sunday nd first against the Mariners.
Mariners: LHP Robbie Ray (2-1, 4.19), last year’s AL Cy Young Award winner, makes his fourth start of the season and first against the Royals.