Foreign exchange

Wise (formerly TransferWise) usually has the best or near the best rates, and their service is excellent. Setting up an account was a bit easier than their competitors. You could receive a debit card as well and can open free accounts in many world currencies.

Wise is excellent. I do personal transfers that arrive in minutes.

For €100k at any bank you should be able to have access to their trading desk to get commercial spreads on foreign exchange, and foreign transfers. Ask your bank.

Wise is great also for smaller regular payments transfer, but for a single large payment like you want, your own bank is the best.

Don't forget that the transfer of that large a sum of money should be setting off money-laundering alarm bells at the recipient bank. It might be a good idea to warn them in advance asking if they want to see proof of the provenance of the money.

CALL the companies and NEGOTiATE.

I used various ones including high street banks, Transferwise and CurrenciesDirect. All the same service, using high street banks, I personally feel has a bit more security and sometimes lower or comparable fees if negotiated.

Always call to negotiate the rates for large sums and do not use the service as is if an online platform. With large sums, I always get better rates or other guarantees.

Indeed, call your banks (recipient and origin) before making the transfer or else anti money laundering kicks in which is just more paperwork but can delay things (rates then may change if not fixed).