CryptPad Forms is the forms module of CryptPad, a collaboration suite that describes itself as end-to-end encrypted and open source. It lets you build questionnaires and polls with text, choice, date and grid questions, page breaks and conditional sections. There are roles for authors, auditors and participants, a closing date, and options to anonymise responses or block guest access. Responses can be exported as CSV or JSON or to a spreadsheet. You use it on the hosted instance cryptpad.fr or on a server of your own.
CryptPad is developed by XWiki SAS in Paris, whose team also administers the flagship instance cryptpad.fr. The software is licensed under the AGPL-3.0 and can be self-hosted; the repository includes a Dockerfile and official Docker images. Other public instances run by third parties also exist. For a European organisation, this is a French, open-source option that you can run entirely under your own control if you wish. The documentation refers to end-to-end encryption, which means the server cannot read the content.