Madrid — Top officials in Spain's year-old Socialist government are barely containing their euphoria over what is termed ''the new attitude of comprehension'' by the French Socialist government after last week's roundup and deportation of ETA guerrillas based in southern France.
Prime Minister Felipe Gonzalez went as far as to claim, ''I think we'll be able to end ETA.'' Other officials even extended their optimism to surmize that ''a new climate has begun that could lead to Spain's entrance into the Common Market under French auspices.''
Deputy Premier Alfonso Guerra said over the weekend he had ''very well-founded, great hopes that the French Socialist government will now prevent ETA terrorists from using French territory to plan actions and elude Spanish justice.''
In addition to the deportations of half a dozen top ETA leaders to Panama, another eight were sent off to northern France in confinement. Although France has previously confined various ETA leaders, last week's crackdown is considered to be a genuine change of attitude.
Here, much of the credit is given to Mr. Gonzalez, who has maintained a campaign, not only with the French government, but also with top officials from the United States, West Germany, Italy, Austria, and Greece. They in turn have pressured France to take measures against ETA guerrillas based in France and to remove obstacles blocking Spanish membership in the European Community.
French officials claim the police action was taken because of ''the climate of progressive violence in the Atlantic Pyrenees.'' Violence broke out in the French Basque country recently with the killing of a top ETA leader, Mikel Goikoetxea, alias Txapela, by a mysterious new right-wing group calling itself Antiterrorist Group of Liberation (GAL). Exiled Basques and left-wing Basque political parties claim the organization is sponsored by top commands of the Spanish police and Civil Guard with official acquiescence. They warn the Gonzalez government ''will face its day of judgment.''
Demonstrations in France and the appearance of a French Basque radical group, called Iparretarrak, evidently began to worry French authorities.
Although the government has denied any knowledge of GAL, the conservative Basque Nationalist Party has speculated vaguely about the possibility of police participation or government knowledge of the group.
A French parliamentary representative publicly claimed that GAL was composed of French activists directed by ''certain members'' of the Spanish police who ''are sustained financially by responsible (authorities) on the other side of the border.''
Spain's ruling Socialist Party announced plans to send an official protest to the French Socialist Party.
Last fall four Spanish police apparently bungled an attempt to kidnap another Basque leader, who was subsequently deported. That incident raised speculation about the Socialists' use of ''dirty tricks'' or illegal warfare in French territory. When questioned about GAL activities recently, Gonzalez insisted ''the only dirty war is being done by ETA.''
Meanwhile, Basque industrialists such as millionaire Luis Olarra unabashedly espouse combating terrorism ''with the same arms and methods.'' Mr. Olarra frequently admits having contacted Mafia hit men to act against ETA in case he or anyone in his family ever becomes a victim of an ETA attack.
In any case, more violence may be in store in spite of government optimism. ETA issued a warning Friday that it plans to kill top Socialist leaders in retaliation for the French roundups and GAL activities.
The Basque Socialist Party leader retorted on state-owned national radio that ''any socialist militants who receive some type of aggression will know how to retaliate, 5 to 1'' and warned, ''for the well-being of the autonomous commands of ETA and in their own interest, I would not touch a single [Basque] socialist. . . .''