Some symbols in table name can cause to Error Code: 1050 when created FK

CREATE TABLE `#departments` (

  `id_depart` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,

  PRIMARY KEY (`id_depart`)

) ENGINE=INNODB;

CREATE TABLE `crm_client` (

  `id_client` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,

  PRIMARY KEY (`id_client`)

) ENGINE=INNODB;

CREATE TABLE `#departments_pos` (

  `id_pos` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,

  `id_depart` INT(10) UNSIGNED NOT NULL,

  `id_client_bank` INT(10) UNSIGNED NOT NULL,

  PRIMARY KEY (`id_pos`),

  KEY `id_depart` (`id_depart`),

  CONSTRAINT `#departments_pos_ibfk_1` FOREIGN KEY (`id_depart`) REFERENCES `#departments` (`id_depart`)

) ENGINE=INNODB;

ALTER TABLE `#departments_pos`  

  ADD FOREIGN KEY (`id_client_bank`) REFERENCES `crm_client`(`id_client`);

Error Code: 1050

Table './test2/@0023departments_pos' already exists

ALTER TABLE `#departments_pos`  

  ADD CONSTRAINT `#departments_pos_ibfk_2` FOREIGN KEY (`id_client_bank`) REFERENCES `crm_client`(`id_client`);

CREATE TABLE `#departaments` (

  `id_depart` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,

  PRIMARY KEY (`id_depart`)

) ENGINE=INNODB DEFAULT CHARSET=utf8

CREATE TABLE `#departaments_tree` (

  `id_depart` INT(10) UNSIGNED NOT NULL,

  `id_depart_in` INT(10) UNSIGNED NOT NULL,

  PRIMARY KEY (`id_depart`,`id_depart_in`),

  CONSTRAINT `#departaments_tree_ibfk_1` FOREIGN KEY (`id_depart`) REFERENCES `#departaments` (`id_depart`)

) ENGINE=INNODB DEFAULT CHARSET=utf8

ALTER TABLE `#departaments_tree`  

  ADD FOREIGN KEY (`id_depart_in`) REFERENCES `#departaments`(`id_depart`)

Error CODE: 1050

TABLE './test3/@0023departaments_tree' already EXISTS

ALTER TABLE `#departaments_tree`  

  ADD CONSTRAINT `#departaments_tree_ibfk_2` FOREIGN KEY (`id_depart_in`) REFERENCES `#departaments`(`id_depart`);