This is a situation I would not have imagined. You are booked to fly Finnair from Helsinki Vantaa airport, their hub, and the ticket is booked in business class, which should give lounge access. You proceed to the Finnair Lounge in the Schengen area, show your boarding pass at the reception desk, and they deny you access.
This is both the positive thing and the tricky thing at the same time with both the OneWorld and Skyteam alliances. In contrast to Star Alliance, when it comes to point earnings (and apparently also other arrangements, such as lounge access in some cases) what you eventually get depends on the marketing carrier rather than the operating carrier. That means in simple terms the airline you have booked the ticket with (look at the flight number) rather than the airline you actually fly.
So in this case I was flying Finnair from Helsinki to Paris. I had a boarding pass where it said Finnair, and I was to travel on a Finnair aircraft with a Finnair crew and was to sit in Finnair business class. But my ticket was booked with Air France, using an AF flight numer, and this meant I was regarded as an Air France passenger.
And for some reason Air France has alternative arrangements in Helsinki. They have contracted the Aspire Lounge, rather than using the Finnair Lounge. To be fair the lounge arrangement was actually very written on the boarding pass. But it was still a very odd situation. And to be honest I would have preferred the Finnair Lounge over the Aspire Lounge.