Here is a very general estimate of costs to own, based on 500 hours of usage per year:
Crew Salaries (2 pilots, 1 flight attendant), €500,000
Maintenance & Repairs, €500,000
Insurance, €200,000
Fuel (Based on 500 hours/year at ~500 liters/hour), €2.5M
Hangar Fees, €100,000
Navigation & Landing Fees, €300,000
Miscellaneous Costs (catering, subscriptions, etc.), €200,000
Total Estimated Annual Cost €4.2M