Yes you can say " à propos de " or " au sujet de". "Il s'agit de...." is ok too. Having said that though, keep in mind that "about" is used in many other contexts in the UK and you can't translate it with "à propos de" when you mean "I'm about to" "what about XYZ?" "I'll be about if you look for me" "it's about time!" and others like that. In those contexts, it's better to ban the word "about "and rephrase your thought with easier words to translate.

the word "about" can be translated in french to " à propos de " or " au sujet de ". IF you wonna say for exemple "in our meeting , we have talked about something" , you say " lors de notre rencontre, nous avons parlé à propos de quelque chose" . you can also use "de" , it depends in the context. good luck