Ms Blauel said she took an overdose of Valium after the star told her "the marriage was not working and that he wanted her to leave" three days into their stay in St Tropez.
The claims emerged as part of Ms Blauel's £3m damages claim against Sir Elton, over allegations he broke the terms of their divorce deal.
The German-born sound engineer was married to Sir Elton for four years, and has kept a low profile since the end of the marriage in 1988.
But she filed legal papers earlier this year, after taking exception to the depiction of their relationship in Sir Elton's 2019 autobiography Me, as well as in the hit movie Rocketman.
The disclosures triggered longstanding mental health problems, her claim said.
In response, Sir Elton's defence acknowledged the existence of the divorce agreement, which both parties signed, but denied any breaches or causing "psychological harm".