PARIS (AP) — Opponents of a law that would raise the retirement age in France from 62 to 64 are making last-ditch plans to prevent the change. The country’s main labor unions on Tuesday called for another round of nationwide demonstrations and strikes on June 6. France’s top constitutional body is expected to rule Wednesday on a request to start a lengthy process that could lead to a bill or a referendum to restore the minimum retirement age of 62. Regardless of what the Constitutional Council decides, its ruling doesn’t keep the age 64 law from taking effect in September. A group of opposition lawmakers is championing a separate legislative proposal to bring back the lower retirement age.