Complex sentence: As a teenager, unable to have the opportunity to study and learn a profession of his choice, he reluctantly embraces the career of butcher specialized in horse meat, a profession already frowned upon at the time in France.
Split into simpler sentences: As a teenager, he doesn't have the opportunity to study and learn a profession of his choice. So he reluctantly embraces the career of butcher specialized in horse meat, a profession already frowned upon at the time in France.