SELECT COUNT(distinct p.user_id)
  FROM `friendly--pix.projectId.firebase_predictions.YOUR_PACKAGE_NAME_ANDROID` p CROSS JOIN UNNEST (predictions)
    INNER JOIN  `projectId.analytics_YOUR_TABLE.events_*`` a on p.user_id = a.user_id 
WHERE 
    prediction_name = "churn"   
    AND score > 0.7
    AND TIMESTAMP_TRUNC(p.prediction_time, DAY) = TIMESTAMP('2018-10-04') 
    AND a.geo.country = "France"