PARIS — He has lost much of his hair and, after a 10-day prison hunger strike last month, a bit of his signature paunch. But as he prepares to stand trial on Monday for a series of bombings he is accused of orchestrating in the early 1980s, Ilich Ramírez Sánchez, better known as Carlos the Jackal, seems to have lost little of his bravado.

Although forbidden from communicating with anyone other than his family and his lawyers, Mr. Ramírez managed to organize interviews last month with a French newspaper and a radio station that were conducted using a smuggled mobile phone. In those conversations, the 62-year-old Venezuelan came across as combative and rambling, attacking unspecified “falsifications” in the case against him, though refusing to either admit to or deny the allegations.

“I am not in the habit of making egocentric declarations,” Mr. Ramírez told the newspaper, Libération, when asked whether he was responsible for the bombings. “Nor will I play the prosecution’s pitiful games.”...