Analyze the financial performance of Maison de Luxe based on the following information:

• Net Sales: €1,000,000
• Cost of Goods Sold: €400,000
• Operating Expenses: €300,000
• Interest Expense: €20,000
• Income Tax Expense: €80,000
• Average Total Assets: €2,000,000
• Average Total Equity: €800,000

Calculate the following financial ratios: gross profit margin, operating profit margin, return on assets (ROA), return on equity (ROE), debt-to-equity ratio, and interest coverage ratio.

Interpret the results of the financial ratios and provide recommendations for Maison de Luxe's financial management.