Christine Quinn is back in the "Selling Sunset" spotlight ... and if her first day filming is anything to go by, she's slipping right back into the luxury real estate circus like she never left.

Sources tell TMZ ... cameras were rolling Saturday at the Rosé Day event at the King Gillette Mansion in Calabasas, where production had carved out a VIP section for the cast and their inner circle at the wine-fueled bash.

Cast and crew were posted up around the group capturing all the action ... with Christine front and center and, surprisingly, steering clear of any drama. For now, anyway.

Also in the mix were brokerage bosses Jason and Brett Oppenheim, who were spotted chatting with cast members including Bre Tiesi and Jason's ex, Jessica Vargas.

As we've reported, Season 10 is already shaping up to be a major reset for the Netflix hit after a significant cast shakeup saw some agents shown the door and familiar faces like Christine and Heather brought back into the fold.

And not everyone's mad about it ... outgoing cast member Sandra Vergara recently told us on "The TMZ Podcast" that Christine's return is exactly what the show needs to turn up the heat this season.