Retrieve the payment received from an user via Paypal Oauth?

I'm trying to retrieve the list of payments received (sales) on behalf on an user using Oauth.

I can connect via Oauth successfully, but when I try to retrieve the list of payments with the following request:

r = requests.get(
    'https://api.sandbox.paypal.com/v1/payments/payment',
    headers={'authorization': 'Bearer {0}'.format(access_token)},
    params={
        'count': 100,
        'sort_by': 'create_time',
        'sort_order': 'desc'
    }
)

I get an error from the server: PERMISSION_DENIED

{"name":"PERMISSION_DENIED","message":"No permission for the requested operation","information_link":"https://developer.paypal.com/docs/api/payments/#errors","debug_id":"33d30d1074b1e"}

I'm pretty sure it's related to the scopes I asked when connecting the customer (none for the tests) but when I try to use the following scope:

'scope': "openid https://api.paypal.com/v1/payments/.*"

I get the following error : "Scope invalid".

So, how can I retrieve a list of payments on behalf of a user? (just read access!)