What is the ruling on a young Muslim man studying at a mixed-gender university in France, given his vow to dedicate his studies to Allah and to serving Islam, his determination to engage in Da‘wah, and his fear of temptation? And are there any non-mixed-gender universities in the field of informatics and communications where he could study?

Studying in mixed-gender universities is impermissible except in cases of necessity or dire need. Regarding your specialization, there is no necessity or need for such studies in a mixed-gender university, as it is possible to study this field in non-mixed universities, such as some universities in the Gulf region and elsewhere. Assuming that is not possible, one can study through distance learning at any university that offers this system and does not require the student's physical presence except at the end of the year for examinations, or suffices with their examination in their home country, or suffices with their examination online.