WorldScreen.com made an interesting interview with David Michel (co-founder of Marathon) on Totally Spies! and mixed first Season 6 animations with Totally Spies The Movie scenes in it! We get to see only few moments but it is enough to say for sure that there definetely will be Mandy in S6 and at least part of S6 takes place at Mali-U University from Season 5! Art style of the new season is inherited from TS The Movie and fashionable clothes are also present! TS mix starts at 0:24 in the interview video below:
Here are some screenshots:
Interview: WorldScreen