Flatex requires you to have an existing Computershare account. You can open one by buying a share through Give A Share, or a popular route has been through Interactive Brokers (IBKR). They can DRS quickly and for a $5(US) fee, (link to guide here).
Because of this requirement, Flatex will ask you for a Computershare account number. For security reasons it is not recommended to give this information to your broker, but in this case there may not be another choice. With Computershare accounts, the account number is the "key" that allows brokers to authorize a transfer of shares out of the DRS and back to the broker.
If you provide your account number to initiate the transfer, it is recommended to protect your Computershare account by making a small change to your name or address to block any unauthorized attempts at withdrawing your direct registered shares. Such as adding or removing a middle initial, or making a subtle enough change to your address that you can still receive your snail mail (add or remove a borough, or a space in your postal/zip code).
Only do this when you are confident you are finished transferring your shares from your broker to the DRS, and if you are confident you do not want to move your shares back to your broker.
Please Note; if you have GS2C shares, you can convert them to GME and transfer to IBKR at the same time using this guide.
Flatex may charge a fee of €80 for a DRS transfer. It is still a new process for them, so this may change.
How to transfer:
Once your shares (and €80) are settled in Flatex, you need to use the Flatex Website and send a secure message to the support team indicating that you want to direct register your shares.
Ask for your shares to first be transferred within Clearstream from CBF to CBL (necessary to allow transfers to an external custodian).
Then provide the following information:
Computershare's DTC number: #7807.
GameStop's ISIN: US36467W1099.
Quantity of GME you want to send to Computershare.
Beneficiary owner (bfo): Usually yourself unless you want to gift the shares to somebody else with an existing Computershare account.
Your home address.
Your Flatex account number.
Your Computershare account number.
The support agent will take care of the rest.
Once the request is submitted the transfer will take 5-15 business days to process. If you're feeling uncertain you can check in with them by starting a support chat on Flatex's website.
If you have an existing Computershare account:
Your broker will DRS transfer the shares based on your name and address. As a result, a second account may be created for you. This can be for a few reasons, such as a middle initial existing on one account, but not the other. If your name and address match exactly, then the transfer will process within the normal amount of time. If not, then it will take another 2-4 weeks for the account to be made and the DRS Account Statement sent out to you.
At this stage it is important to verify your tax status as a non-US citizen. While logged into your account, go to the My Profile tab, then “Tax Details”. A guide on how to fill in the W-8 BEN form is linked here).
You must fill in the W-8 BEN form before you buy any shares through Computershare, or add your banking information (especially if it's a US dollar account). Otherwise you will be assumed to be a US citizen.