Which level of hurdle rate is now acceptable in European VC

It's not common to see hurdle rates for funds less then $30m, even in the EU. Small funds are optimized for the carry, not for fees. So, when you insert a hurdle, you're going to have mis-aligned incentives and expectations with your LPs because they are reducing your carry with this approach AND forcing you to use a European Waterfall vs American which is much less advantageous for small funds.

To answer your question: There is no bench mark for VC. It's super uncommon for VCs to have hurdles. For the Private Equity asset class, hurdles are usually in the 5% - 10% range. But again, these are typically applied to funds in the $100m+ range.

IMPORTANT: Avoid hurdles at all costs. Read into the intent of the LP rather then the 'ask'. Most LPs that are asking for this will be bad LPs because they are not aligned with your goals and expectations. You will need to mange these bad LPs for 10+ years.