To estimate a maximum purchase price for the coin that is going to be auctioned, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

1. Current Condition: The coin has a condition of 95 (S/C-), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Previous Auction Prices: By looking at the auction prices of coins with a similar condition (95), we find that at the auction on 2020-03-12, the coin was auctioned with a starting price of 2200 euros and sold for 8000 euros. This suggests that there is significant potential for a coin in this condition to reach high prices.

3. Current Starting Price: The starting price of 6000 euros is considerably higher than the average starting price of 284.84 euros and the average hammer price of 375.6 euros. This indicates that the auction house has high expectations for this coin.

4. Sales Trends: The coin has been auctioned 95 times, of which it has sold 85 times. This suggests that there is consistent interest in this coin, which may influence its price.

5. Maximum Price Estimation: Given that the coin has a high condition and has reached significant hammer prices in the past, a reasonable maximum purchase price could be 20-30% higher than the starting price, considering the demand and the condition of the coin.

Therefore, an estimated maximum purchase price could be between 7200 and 7800 euros. This is based on the expectation that bidders are willing to pay a premium for the high condition and the historical auction prices.