code: public FrenchRepublicanMonth getMonth() {
  
          if (this.fdoy > 360) {
              throw new ChronoException(
                  "Complementary days (sansculottides) do not represent any month: " + this.toString());
          }
  
          int m = ((this.fdoy - 1) / 30) + 1;
          return FrenchRepublicanMonth.valueOf(m);
  
      }
docs: /*[deutsch]
  <p>Liefert den republikanischen Monat, wenn vorhanden. </p>
  
  @return  month enum
  @throws  ChronoException if this date is a complementary day
  @see     #MONTH_OF_YEAR
  @see     #hasSansculottides()
  @see     #hasMonth()