IF XYZ (India) is 'supplier' of subject services and PQR(Germany) is recipient of those services, THEN GST will be payable (of course, excluding services falling under zero-rated supplies u/s 16 of the IGST Act, 2017).
However, one needs to look into entire arrangements between Parent Co. and Indian subsidiary (including who is providing what services to whom), what was purpose / context of these business trips in those arrangements and under what capacity the parent co. is reimbursing these expenses, before concluding that XYZ (India) is indeed 'supplier' of subject services & PQR(Germany) is the 'recipient'.
Because of multiple possibilities based on factual scenario (to be looked into in its entirety), I find difficulties to give my views - one way or other - on the issue raises only the basis of payment of certain expenses made by Indian subsidiary and its reimbursement from parent foreign Co.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion.