I'm a software engineer in a consultancy company. I've worked there for several years and until last November, I worked in the main offices on internal, deep learning-based projects.

My company then sent me to work as a consultant for a client, and my mission has nothing to do with deep learning anymore. However, my company sometimes calls me for coming back temporarily and work on deep learning projects that they recently came up with.

They've called me to come back a couple of times since I'm at the client's offices and I'm sometimes very uncomfortable with what they're asking me to develop. Most of the time they want me to design solutions that would fulfill purposes that I personally find unethical (for instance, targeted advertisement in stores based on body appearance. Although it's legally authorized, I think it's dishonest because people know they're under video surveillance but they don't know that their data is processed for commercial purposes).

Can I refuse to work on the projects that I think are unethical? Should I tell them why I'd rather not work on those?

Additional info:

• I should add that I'm the most skilled in feature recognition in my company (and the only one who's skilled in artificial intelligence). They don't have much choice but to ask me.
• I'm working in the French offices of an international corporation.
• Also, please note that I'm not looking for opinions on whether such projects are indeed unethical.