The longtime AMQ Creative Director -- who succeeded McQueen himself following his death in 2010, serving as a trailblazer -- trotted out her unique style for the Spring/Summer 2024 line Saturday during Paris Fashion Week ... which will be her last as head of the brand.

Her models certainly didn't disappoint ... carrying themselves with elegance and grace as they walked up and down the runway, proudly rocking SB's swan song designs.

A familiar face was also in the mix ... Naomi Campbell -- who's worked with McQueen a lot over the years -- did her famous strut in a Burton-made gown ... and she even appears to have shed a tear to close out the show, just proving this is truly the end of an era.

Burton announced her departure from Alexander McQueen earlier this month -- although no official reason was given by parent company Kering ... and no successor has been named.

At the time, SB simply said ... "“I am so proud of everything I’ve done and of my incredible team at Alexander McQueen. I am looking forward to the future and my next chapter and will always carry this treasured time with me." No word on where she's going next.

Like we said ... Burton's exit caps off a trailblazing career full of highlights -- one of which included Sarah designing Kate Middleton's gorgeous wedding dress in 2011 ... something the entire world got to witness during her marriage to Prince William.

She's won a ton of awards, and her fashion sensibilities have been lauded for a long time.

You can tell just how respected she is by her contemporaries ... because Vogue's very own EIC Anna Wintour was also on hand Saturday to send Sarah off right -- giving her a big hug.